Return a default constructed vector from Configurator::UpdateUrl

Certain toolchains require a constructor to create the vector.

patches/core/inox-patchset/0015-disable-update-pings.patch

@@ -5,7 +5,7 @@
  
  std::vector<GURL> Configurator::UpdateUrl() const {
 -  return external_constants_->UpdateURL();
-+  return std::vector<GURL>;
++  return std::vector<GURL>();
  }
  
  std::vector<GURL> Configurator::PingUrl() const {