Remove trailing semicolons at the end of functions.

./dbus/object_manager_adaptor.cc:171:  You don't need a ; after a }  [readability/braces] [4]
./extensions/browser/xwalk_extension_function_handler.h:40:  You don't need a ; after a }  [readability/braces] [4]
Merge pull request #2714 from rakuco/readability-braces-warnings

Remove trailing semicolons at the end of functions.