largefiles: support revsets for revert

Previous to this, revert only accepted revsets if the largefiles extension was
disabled.

hgext/largefiles/overrides.py

@@ -567,7 +567,7 b' def overriderevert(orig, ui, repo, *pats'
                 os.unlink(repo.wjoin(lfutil.standin(lfile)))
 
         try:
-            ctx = repo[opts.get('rev')]
+            ctx = scmutil.revsingle(repo, opts.get('rev'))
             oldmatch = None # for the closure
             def overridematch(ctx, pats=[], opts={}, globbed=False,
                     default='relpath'):

tests/test-largefiles.t

@@ -869,6 +869,8 b' revert some files to an older revision'
   reverting .hglf/sub2/large6 (glob)
   $ cat sub2/large6
   large6
+  $ hg revert --no-backup -C -r '.^' sub2
+  reverting .hglf/sub2/large6 (glob)
   $ hg revert --no-backup sub2
   reverting .hglf/sub2/large6 (glob)
   $ hg status