... and default to C_GLOBAL. A rather common case.
Similar for ActionContainer::addSeparator().
Change-Id: I7f9ba573af201c0a472132d5a494ad17cc4175b7
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>