fix no_proxy_str memory leak

src/core/ext/filters/client_channel/http_proxy.cc

@@ -115,6 +115,7 @@ static bool proxy_mapper_map_name(grpc_proxy_mapper* mapper,
               "unable to split host and port, not checking no_proxy list for "
               "host '%s'",
               server_uri);
+      gpr_free(no_proxy_str);
     } else {
       size_t uri_len = strlen(server_host);
       char** no_proxy_hosts;
@@ -139,6 +140,7 @@ static bool proxy_mapper_map_name(grpc_proxy_mapper* mapper,
       gpr_free(no_proxy_hosts);
       gpr_free(server_host);
       gpr_free(server_port);
+      gpr_free(no_proxy_str);
       if (!use_proxy) goto no_use_proxy;
     }
   }