Help: Remove extra event processing

It's not clear why we need it there, it's generally not advisable to do
qApp->processEvents() and in this case it clearly creates problems.

Change-Id: I2707ef0ec98ee761078283ee3ce3f76f9da95f31
Task-number: QTCREATORBUG-14215
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>