BUG/MEDIUM: resolvers: Make 1st server of a template take part to SRV resolution

The commit 3406766d5 ("MEDIUM: resolvers: add a ref between servers and srv
request or used SRV record") introduced a regression. The first server of a
template based on SRV record is no longer resolved. The same bug exists for
a normal server based on a SRV record.

In fact, the server used during parsing (used as reference when a
server-template line is parsed) is never attached to the corresponding srvrq
object. Thus with following lines, no resolution is performed because
"srvrq->attached_servers" is empty:

  server-template test 1 _http.domain.tld resolvers dns ...
  server test1 _http.domain.tld resolvers dns ...

This patch should fix the issue #1295 (but not confirmed yet it is the same
bug). It must be backported everywhere the above commit is.

(cherry picked from commit 81ba74ae5061bc55b3460f01a99371281de8f7f3)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/server.c b/src/server.c
index d6cf7ef..586fa02 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2474,6 +2474,7 @@
 					err_code |= ERR_ALERT | ERR_FATAL;
 					goto out;
 				}
+				LIST_APPEND(&newsrv->srvrq->attached_servers, &newsrv->srv_rec_item);
 			}
 			else if (srv_prepare_for_resolution(newsrv, fqdn) == -1) {
 				memprintf(errmsg, "Can't create DNS resolution for server '%s'",