largefiles: port revset registration to exthelper

This tests the merge code that wasn't tested in the previous patch.

hgext/largefiles/__init__.py

@@ -192,4 +192,4 b' def _uisetup(ui):'
             extensions.wrapfunction(module, 'rebase',
                                     overrides.overriderebase)
 
-revsetpredicate = overrides.revsetpredicate
+revsetpredicate = eh.revsetpredicate

hgext/largefiles/overrides.py

@@ -32,7 +32,6 b' from mercurial import ('
     merge,
     pathutil,
     pycompat,
-    registrar,
     scmutil,
     smartset,
     subrepo,
@@ -888,9 +887,7 b' def exchangepushoperation(orig, *args, *'
     pushop.lfrevs = lfrevs
     return pushop
 
-revsetpredicate = registrar.revsetpredicate()
-
-@revsetpredicate('pulled()')
[e-mail]('pulled()')
 def pulledrevsetsymbol(repo, subset, x):
     """Changesets that just has been pulled.