message: Fix interface renaming
  Summary:
  Interface renaming was not taking into account external interfaces and renaming them causing an instacrash
  build[automation_fbandroid_redexunstable_]
diff: @@ -295,6 +295,11 @@ int VirtualRenamer::rename_interface_scopes(int& seed) const {
  if (type_class(scope->type)->is_external()) return;
  if (!can_rename_scope(scope)) return;
  }
  + for (const auto& intf : intfs) {
  + const auto& intf_cls = type_class(intf);
  + if (intf_cls == nullptr) return;
  + if (intf_cls->is_external()) return;
  + }
  // if any interface method that we are about to rename
  // cannot be renamed give up
  for (const auto& intf : intfs) {
  @@ -413,10 +418,12 @@ size_t rename_virtuals(Scope& classes) {
  const auto obj_t = get_object_type();
  int seed = 0;
  size_t renamed = vr.rename_virtual_scopes(obj_t, seed);
  + TRACE(OBFUSCATE, 2, "Virtual renamed: %ld\n", renamed);
  // rename interfaces
  std::unordered_set<const VirtualScope*> visited;
  - renamed += vr.rename_interface_scopes(seed);
  + size_t intf_renamed = vr.rename_interface_scopes(seed);
  + TRACE(OBFUSCATE, 2, "Interface renamed: %ld\n", intf_renamed);
  TRACE(OBFUSCATE, 2, "MAX seed: %d\n", seed);
  - return renamed;
  + return renamed + intf_renamed;
  }
  