MINOR: contrib/prometheus-exporter: Follow best practices about metrics type

In short, _total metrics are now counters and others are gauges.

No backport needed. See issue #81 on github.
diff --git a/contrib/prometheus-exporter/service-prometheus.c b/contrib/prometheus-exporter/service-prometheus.c
index bf94b85..e6fe1dd 100644
--- a/contrib/prometheus-exporter/service-prometheus.c
+++ b/contrib/prometheus-exporter/service-prometheus.c
@@ -893,50 +893,50 @@
 	[INF_NAME]                           = IST("untyped"),
 	[INF_VERSION]                        = IST("untyped"),
 	[INF_RELEASE_DATE]                   = IST("untyped"),
-	[INF_NBTHREAD]                       = IST("counter"),
-	[INF_NBPROC]                         = IST("counter"),
-	[INF_PROCESS_NUM]                    = IST("counter"),
+	[INF_NBTHREAD]                       = IST("gauge"),
+	[INF_NBPROC]                         = IST("gauge"),
+	[INF_PROCESS_NUM]                    = IST("gauge"),
 	[INF_PID]                            = IST("untyped"),
 	[INF_UPTIME]                         = IST("untyped"),
-	[INF_UPTIME_SEC]                     = IST("counter"),
-	[INF_MEMMAX_MB]                      = IST("counter"),
+	[INF_UPTIME_SEC]                     = IST("gauge"),
+	[INF_MEMMAX_MB]                      = IST("gauge"),
 	[INF_POOL_ALLOC_MB]                  = IST("gauge"),
 	[INF_POOL_USED_MB]                   = IST("gauge"),
 	[INF_POOL_FAILED]                    = IST("counter"),
-	[INF_ULIMIT_N]                       = IST("counter"),
+	[INF_ULIMIT_N]                       = IST("gauge"),
 	[INF_MAXSOCK]                        = IST("gauge"),
 	[INF_MAXCONN]                        = IST("gauge"),
 	[INF_HARD_MAXCONN]                   = IST("gauge"),
 	[INF_CURR_CONN]                      = IST("gauge"),
 	[INF_CUM_CONN]                       = IST("counter"),
 	[INF_CUM_REQ]                        = IST("counter"),
-	[INF_MAX_SSL_CONNS]                  = IST("counter"),
+	[INF_MAX_SSL_CONNS]                  = IST("gauge"),
 	[INF_CURR_SSL_CONNS]                 = IST("gauge"),
 	[INF_CUM_SSL_CONNS]                  = IST("counter"),
-	[INF_MAXPIPES]                       = IST("counter"),
-	[INF_PIPES_USED]                     = IST("gauge"),
-	[INF_PIPES_FREE]                     = IST("gauge"),
+	[INF_MAXPIPES]                       = IST("gauge"),
+	[INF_PIPES_USED]                     = IST("counter"),
+	[INF_PIPES_FREE]                     = IST("counter"),
 	[INF_CONN_RATE]                      = IST("gauge"),
-	[INF_CONN_RATE_LIMIT]                = IST("counter"),
-	[INF_MAX_CONN_RATE]                  = IST("counter"),
+	[INF_CONN_RATE_LIMIT]                = IST("gauge"),
+	[INF_MAX_CONN_RATE]                  = IST("gauge"),
 	[INF_SESS_RATE]                      = IST("gauge"),
-	[INF_SESS_RATE_LIMIT]                = IST("counter"),
-	[INF_MAX_SESS_RATE]                  = IST("counter"),
+	[INF_SESS_RATE_LIMIT]                = IST("gauge"),
+	[INF_MAX_SESS_RATE]                  = IST("gauge"),
 	[INF_SSL_RATE]                       = IST("gauge"),
-	[INF_SSL_RATE_LIMIT]                 = IST("counter"),
-	[INF_MAX_SSL_RATE]                   = IST("counter"),
+	[INF_SSL_RATE_LIMIT]                 = IST("gauge"),
+	[INF_MAX_SSL_RATE]                   = IST("gauge"),
 	[INF_SSL_FRONTEND_KEY_RATE]          = IST("gauge"),
-	[INF_SSL_FRONTEND_MAX_KEY_RATE]      = IST("counter"),
+	[INF_SSL_FRONTEND_MAX_KEY_RATE]      = IST("gauge"),
 	[INF_SSL_FRONTEND_SESSION_REUSE_PCT] = IST("gauge"),
 	[INF_SSL_BACKEND_KEY_RATE]           = IST("gauge"),
-	[INF_SSL_BACKEND_MAX_KEY_RATE]       = IST("counter"),
+	[INF_SSL_BACKEND_MAX_KEY_RATE]       = IST("gauge"),
 	[INF_SSL_CACHE_LOOKUPS]              = IST("counter"),
 	[INF_SSL_CACHE_MISSES]               = IST("counter"),
-	[INF_COMPRESS_BPS_IN]                = IST("gauge"),
-	[INF_COMPRESS_BPS_OUT]               = IST("gauge"),
-	[INF_COMPRESS_BPS_RATE_LIM]          = IST("counter"),
+	[INF_COMPRESS_BPS_IN]                = IST("counter"),
+	[INF_COMPRESS_BPS_OUT]               = IST("counter"),
+	[INF_COMPRESS_BPS_RATE_LIM]          = IST("gauge"),
 	[INF_ZLIB_MEM_USAGE]                 = IST("gauge"),
-	[INF_MAX_ZLIB_MEM_USAGE]             = IST("counter"),
+	[INF_MAX_ZLIB_MEM_USAGE]             = IST("gauge"),
 	[INF_TASKS]                          = IST("gauge"),
 	[INF_RUN_QUEUE]                      = IST("gauge"),
 	[INF_IDLE_PCT]                       = IST("gauge"),
@@ -949,7 +949,7 @@
 	[INF_ACTIVE_PEERS]                   = IST("gauge"),
 	[INF_CONNECTED_PEERS]                = IST("gauge"),
 	[INF_DROPPED_LOGS]                   = IST("counter"),
-	[INF_BUSY_POLLING]                   = IST("counter"),
+	[INF_BUSY_POLLING]                   = IST("gauge"),
 };
 
 /* Type for all stats fields. "untyped" is used for unsupported field. */
@@ -957,9 +957,9 @@
 	[ST_F_PXNAME]         = IST("untyped"),
 	[ST_F_SVNAME]         = IST("untyped"),
 	[ST_F_QCUR]           = IST("gauge"),
-	[ST_F_QMAX]           = IST("counter"),
+	[ST_F_QMAX]           = IST("gauge"),
 	[ST_F_SCUR]           = IST("gauge"),
-	[ST_F_SMAX]           = IST("counter"),
+	[ST_F_SMAX]           = IST("gauge"),
 	[ST_F_SLIM]           = IST("gauge"),
 	[ST_F_STOT]           = IST("counter"),
 	[ST_F_BIN]            = IST("counter"),
@@ -989,7 +989,7 @@
 	[ST_F_TYPE]           = IST("untyped"),
 	[ST_F_RATE]           = IST("untyped"),
 	[ST_F_RATE_LIM]       = IST("gauge"),
-	[ST_F_RATE_MAX]       = IST("counter"),
+	[ST_F_RATE_MAX]       = IST("gauge"),
 	[ST_F_CHECK_STATUS]   = IST("untyped"),
 	[ST_F_CHECK_CODE]     = IST("untyped"),
 	[ST_F_CHECK_DURATION] = IST("gauge"),
@@ -1001,7 +1001,7 @@
 	[ST_F_HRSP_OTHER]     = IST("counter"),
 	[ST_F_HANAFAIL]       = IST("counter"),
 	[ST_F_REQ_RATE]       = IST("untyped"),
-	[ST_F_REQ_RATE_MAX]   = IST("counter"),
+	[ST_F_REQ_RATE_MAX]   = IST("gauge"),
 	[ST_F_REQ_TOT]        = IST("counter"),
 	[ST_F_CLI_ABRT]       = IST("counter"),
 	[ST_F_SRV_ABRT]       = IST("counter"),
@@ -1032,7 +1032,7 @@
 	[ST_F_MODE]           = IST("untyped"),
 	[ST_F_ALGO]           = IST("untyped"),
 	[ST_F_CONN_RATE]      = IST("untyped"),
-	[ST_F_CONN_RATE_MAX]  = IST("counter"),
+	[ST_F_CONN_RATE_MAX]  = IST("gauge"),
 	[ST_F_CONN_TOT]       = IST("counter"),
 	[ST_F_INTERCEPTED]    = IST("counter"),
 	[ST_F_DCON]           = IST("counter"),