Undefine another ENUM_CASE macro after use

This avoids collisions in jumbo/unity builds.

Change-Id: Ibd47b3c0be950c6f9fb5baf206612203c99e9b35
Reviewed-on: https://chromium-review.googlesource.com/827132Reviewed-by: Pavel Yatsuk <pavely@chromium.org>
Commit-Queue: Jens Widell <jl@opera.com>
Cr-Commit-Position: refs/heads/master@{#524351}

components/sync/protocol/sync_protocol_error.cc

@@ -47,6 +47,8 @@ const char* GetClientActionString(ClientAction action) {
   return "";
 }
 
+#undef ENUM_CASE
+
 SyncProtocolError::SyncProtocolError()
     : error_type(UNKNOWN_ERROR), action(UNKNOWN_ACTION) {}