BUG/MINOR: resolvers: Add missing case-insensitive comparisons of DNS hostnames

DNS hostname comparisons were fixed to be case-insensitive (see b17b88487
"BUG/MEDIUM: dns: Consider the fact that dns answers are
case-insensitive"). However 2 comparisons are still case-sensitive.

This patch must be backported as far as 1.8.

(cherry picked from commit 59b29257338f8e7fb6def6bddda45d08651ffe1c)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/server.c b/src/server.c
index 7c1dd98..0c340d3 100644
--- a/src/server.c
+++ b/src/server.c
@@ -4068,7 +4068,7 @@
 		HA_SPIN_LOCK(SERVER_LOCK, &tmpsrv->lock);
 		if ((tmpsrv->hostname_dn == NULL) ||
 		    (srv->hostname_dn_len != tmpsrv->hostname_dn_len) ||
-		    (strcmp(srv->hostname_dn, tmpsrv->hostname_dn) != 0) ||
+		    (strcasecmp(srv->hostname_dn, tmpsrv->hostname_dn) != 0) ||
 		    (srv->puid == tmpsrv->puid)) {
 			HA_SPIN_UNLOCK(SERVER_LOCK, &tmpsrv->lock);
 			continue;
@@ -4147,7 +4147,8 @@
 	resolution = (srv->dns_requester ? srv->dns_requester->resolution : NULL);
 	if (resolution &&
 	    resolution->hostname_dn &&
-	    !strcmp(resolution->hostname_dn, hostname_dn))
+	    resolution->hostname_dn_len == hostname_dn_len &&
+	    strcasecmp(resolution->hostname_dn, hostname_dn) == 0)
 		goto end;
 
 	dns_unlink_resolution(srv->dns_requester, 0);