C++: remove warning about stray comma after last enumerator

Although it's a C++11 feature, all sane compilers support it as an
extension to C++03/C++98.

Change-Id: I3c7b0db345d0b175554534e879717f4d14f48b0f
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>