Open documents view: do not switch editor on right-click

Right-clicking opens the context menu, which should not switch editors.

Task-number: QTCREATORBUG-8178
Change-Id: I9c70ba14fa4f80d3fc90fa80954f9f9417a52a98
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Utils::FileName: Enable qDebug() << Utils::FileName()

Change-Id: Iab3663839c25e09426c24472ae241ef7a2d6a069
Reviewed-by: Eike Ziller <eike.ziller@digia.com>