[gold][patch] Fix gold plugins so cleanup handler is not called repeatedly

[Ian Lance Taylor]

Cary Coutant <ccoutant@google.com> writes:

> 	* plugin.h (Plugin::Plugin): Initialize cleanup_done_.
> 	(Plugin::cleanup_done_): New member.
> 	(Plugin_manager::Plugin_manager): Remove cleanup_done_.
> 	(Plugin_manager::cleanup_done_): Remove.
> 	(Plugin_manager::add_input_file): Edit error message.
> 	* plugin.cc (Plugin::cleanup): Test and set cleanup_done_.
> 	(Plugin_manager::cleanup): Remove use of cleanup_done_.

This is OK.

Thanks.

Ian