[Eric] ProjectMenu after cancelling VCS->New from Repository

[Christof Hanke]

Hi,

after performing :

* select Project->Version Control->New From Repository
* choose SVN
* press "Cancel" in "New from Repository" - Dialog

the menu-entry of Project->Version Control is still that of "svn", which
is IMHO incorrect, because I have not opened any project.

Apparently self.vcsProjectHelper in Project/Project.py does not get
reset to "None" after the action ("New from Repository") is cancelled,
which happens when the action is failing (e.g. when there's no binary to
call).

Versions:
latest snapshots of everything.

Christof