Missing keybinding for C-x C-q in experimental vc*.el

[Neal Becker]

I'm very excited about this new vc.el!  I am trying it with mercurial.el. 
So far so good.

For a _LONG_ time I have hoped to try all the new distributed rcs like
darcs, mercurial, bzr-ng, but the emacs integration have typically not
worked because of vc problems.

I hope this will move from experiment to reality soon.