bug#3570: 23.0.94; vc-default-revision-granularity missing argument

[Magnus Henoch]

Package: emacs,vc
Severity: minor

The function vc-default-revision-granularity should accept a backend
argument, but doesn't.  This gives users of outdated third-party VC
backends confusing error messages at times.

To reproduce:
(progn
  (provide 'vc-foo)
  (vc-call-backend 'foo 'revision-granularity))

Expected: (error "Your backend will not work with this version of VC mode.")
Actual result: wrong-number-of-arguments

Regards,
Magnus