[gmenu-dbusmenu-proxy] Don't create ~/.gtkrc-2.0

Summary: BUG: 412970

Test Plan: GTK-2.0 applications use breeze again. Global menu activation still works.

Reviewers: broulik

Reviewed By: broulik

Subscribers: plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D24664