Way to ignore .hgrc?

[Neal Becker]

I posted this to emacs-devel:

Neal Becker <ndbecker2 at gmail.com> writes:

  > hg status test_front_end_spec.py
  > *** failed to import extension rdiff: No module named rdiff
  > ? test_front_end_spec.py
  > 
  > The above warning confuses emacs.  C-x v i report 'already 
registered'.

Indeed, vc-hg-status parses the result of "hg status 
test_front_end_spec.py"

Is there are way to tell hg to ignore .hgrc ?  I.E. something like emacs 
-q ?

  > After I fixed the above warning (removed rdiff from my .hgrc), then 
C-x 
  > v i worked correctly.