Completion: Apply perfect match whenever not invoked explicitly

This should not only be when the editor is idle but whenever the
completion was not invoked explicitly.

Change-Id: I0f3dbbe2f5db66ae3e1f57c7039a93f74f31e1dc
Reviewed-on: http://codereview.qt.nokia.com/130


Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>