bug#50344: C-x v keybinding for vc-print-branch-log

[Gregory Heytings]

> > > It makes no sense to develop branch commands without 'C-x v b' 
> > > binding.
> >
> > If C-x v b isn't available anymore, perhaps C-x v < or ^ would be a 
> > good alternative?
>
> For vc-switch-backend?

No, for vc-branch-* commands.  vc-switch-backend is already on C-x v b.