BUG/MINOR: mux_h2: fix incorrect stat titles

Duplicate titles for the stats H2_ST_{OPEN,TOTAL}_{CONN,STREAM}. These
entries are used on csv for the heading.

This must be backported up to 2.3.

This fixes the github issue #1102.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 2de155f..511975b 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -432,9 +432,9 @@
 	                         .desc = "Count of currently open connections" },
 	[H2_ST_OPEN_STREAM]  = { .name = "h2_backend_open_streams",
 	                         .desc = "Count of currently open streams" },
-	[H2_ST_TOTAL_CONN]   = { .name = "h2_open_connections",
+	[H2_ST_TOTAL_CONN]   = { .name = "h2_total_connections",
 	                         .desc = "Total number of connections" },
-	[H2_ST_TOTAL_STREAM] = { .name = "h2_backend_open_streams",
+	[H2_ST_TOTAL_STREAM] = { .name = "h2_backend_total_streams",
 	                         .desc = "Total number of streams" },
 };