Open project if it was not added to VC system.

Currently project will be created, but if it fails to add it to VC
system, it asks user to open project anyway.

Task-number: QTCREATORBUG-8892
Change-Id: I8d6cfad4a5d6b4810491d355f916dfe031e82a52
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>