MINOR: server: remove a few unneeded LIST_INIT calls after LIST_DEL_LOCKED

Since LIST_DEL_LOCKED() and LIST_POP_LOCKED() now automatically reinitialize
the removed element, there's no need for keeping this LIST_INIT() call in the
idle connection code.
diff --git a/src/backend.c b/src/backend.c
index ace0ca4..dfdb9b5 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1308,11 +1308,9 @@
 		    (((s->be->options & PR_O_REUSE_MASK) != PR_O_REUSE_NEVR) &&
 		     s->txn && (s->txn->flags & TX_NOT_FIRST)))) {
 			srv_conn = LIST_POP_LOCKED(&srv->idle_orphan_conns[tid],
-			    struct connection *, list);
-			if (srv_conn) {
-				LIST_INIT(&srv_conn->list);
+			                           struct connection *, list);
+			if (srv_conn)
 				reuse_orphan = 1;
-			}
 		}
 
 		/* If we've picked a connection from the pool, we now have to