MINOR: server: Make 'default-server' support 'check-send-proxy' keyword.

This patch makes 'default-server' directive support 'check-send-proxy' setting.
A new keyword 'no-check-send-proxy' has been added so that to disable
'check-send-proxy' setting both in 'server' and 'default-server' directives.
diff --git a/src/server.c b/src/server.c
index 2b0a5da..796ff51 100644
--- a/src/server.c
+++ b/src/server.c
@@ -221,6 +221,14 @@
 	return 0;
 }
 
+/* Parse the "check-send-proxy" server keyword */
+static int srv_parse_check_send_proxy(char **args, int *cur_arg,
+                                      struct proxy *curproxy, struct server *newsrv, char **err)
+{
+	newsrv->check.send_proxy = 1;
+	return 0;
+}
+
 /* parse the "id" server keyword */
 static int srv_parse_id(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
 {
@@ -261,6 +269,14 @@
 	return 0;
 }
 
+/* Parse the "no-check-send-proxy" server keyword */
+static int srv_parse_no_check_send_proxy(char **args, int *cur_arg,
+                                         struct proxy *curproxy, struct server *newsrv, char **err)
+{
+	newsrv->check.send_proxy = 0;
+	return 0;
+}
+
 /* Shutdown all connections of a server. The caller must pass a termination
  * code in <why>, which must be one of SF_ERR_* indicating the reason for the
  * shutdown.
@@ -871,8 +887,10 @@
  */
 static struct srv_kw_list srv_kws = { "ALL", { }, {
 	{ "backup",       srv_parse_backup,       0,  1 }, /* Flag as backup server */
+	{ "check-send-proxy",    srv_parse_check_send_proxy,    0,  1 }, /* enable PROXY protocol for health checks */
 	{ "id",           srv_parse_id,           1,  0 }, /* set id# of server */
 	{ "no-backup",    srv_parse_no_backup,    0,  1 }, /* Flag as non-backup server */
+	{ "no-check-send-proxy", srv_parse_no_check_send_proxy, 0,  1 }, /* disable PROXY protol for health checks */
 	{ NULL, NULL, 0 },
 }};
 
@@ -1191,6 +1209,7 @@
 						= curproxy->defsrv.iweight;
 
 			newsrv->check.status	= HCHK_STATUS_INI;
+			newsrv->check.send_proxy = curproxy->defsrv.check.send_proxy;
 			newsrv->check.rise	= curproxy->defsrv.check.rise;
 			newsrv->check.fall	= curproxy->defsrv.check.fall;
 			newsrv->check.health	= newsrv->check.rise;	/* up, but will fall down at first failure */
@@ -1535,10 +1554,6 @@
 				newsrv->pp_opts |= SRV_PP_V2;
 				cur_arg ++;
 			}
-			else if (!defsrv && !strcmp(args[cur_arg], "check-send-proxy")) {
-				newsrv->check.send_proxy = 1;
-				cur_arg ++;
-			}
 			else if (!strcmp(args[cur_arg], "weight")) {
 				int w;
 				w = atol(args[cur_arg + 1]);