registrar: Improve error handling

(cherry picked from commit 1875c58)

Author: liviuchircu

lib/reg/lookup.c

@@ -56,7 +56,7 @@ lookup_rc lookup(struct sip_msg *req, udomain_t *d,
 	int idx = 0, nbranches = 0, tlen;
 	char *turi;
 	qvalue_t tq;
-	urecord_t* r;
+	urecord_t* r = NULL;
 	str aor;
 	ucontact_t *ct, **ptr, **pn_cts, **cts;
 	int max_latency = 0, ruri_is_pushed = 0;
@@ -197,6 +197,7 @@ lookup_rc lookup(struct sip_msg *req, udomain_t *d,
 		/* relsease old aor lock */
 		ul.release_urecord(r, 0);
 		ul.unlock_udomain(d, &aor);
+		r = NULL;
 
 	next_aor:
 		aor_uri = &branch_uris[idx];