sanity: free parsed proxy-required header in case of failure

- reported by GH #1990

src/modules/sanity/sanity.c

@@ -698,6 +698,10 @@ int check_proxy_require(sip_msg_t* msg) {
 				}
 				LM_DBG("checking proxy require failed\n");
 				if (u) pkg_free(u);
+				if (msg->proxy_require->parsed) {
+					free_str_list(msg->proxy_require->parsed);
+					msg->proxy_require->parsed = NULL;
+				}
 				return SANITY_CHECK_FAILED;
 			}
 			else {