BUG/MINOR: tcpcheck: Update .health threshold of agent inside an agent-check

If an agent-check is configured for a server, When the response is parsed,
the .health threshold of the agent must be updated on up/down/stopped/fail
command and not the threshold of the health-check. Otherwise, the
agent-check will compete with the health-check and may mark a DOWN server as
UP.

This patch should fix the issue #1176. It must be backported as far as 2.2.
diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index 37d3b38..535c82c 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -836,22 +836,22 @@
 
 		/* first, health statuses */
 		if (strcasecmp(cmd, "up") == 0) {
-			check->server->check.health = check->server->check.rise + check->server->check.fall - 1;
+			check->health = check->rise + check->fall - 1;
 			status = HCHK_STATUS_L7OKD;
 			hs = cmd;
 		}
 		else if (strcasecmp(cmd, "down") == 0) {
-			check->server->check.health = 0;
+			check->health = 0;
 			status = HCHK_STATUS_L7STS;
 			hs = cmd;
 		}
 		else if (strcasecmp(cmd, "stopped") == 0) {
-			check->server->check.health = 0;
+			check->health = 0;
 			status = HCHK_STATUS_L7STS;
 			hs = cmd;
 		}
 		else if (strcasecmp(cmd, "fail") == 0) {
-			check->server->check.health = 0;
+			check->health = 0;
 			status = HCHK_STATUS_L7STS;
 			hs = cmd;
 		}