ProjectWizard: Prevent crash on changes to VCS settings

The ProjectExtension kept a pointer to a page which is destroyed
once the wizard is done and accessed it whenever VCS settings
were touched.

Task-number: QTCREATORBUG-9412
Change-Id: Iabe33d877a3d614ab7470c5e11fe26f7de1bb69c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Debugger: Work on LLDB dumpers

54 passed, 122 failed (lldb 300.99/gcc)

Change-Id: I71e1666c542406b126214c2b9b8b56193bcbcf76
Reviewed-by: hjk <hjk121@nokiamail.com>