largefiles: use wrappedfunction() for util.copyfile() override

Differential Revision: https://phab.mercurial-scm.org/D5866

hgext/largefiles/overrides.py

@@ -686,10 +686,8 b' def overridecopy(orig, ui, repo, pats, o'
             else:
                 listpats.append(makestandin(pat))
 
-        try:
-            origcopyfile = util.copyfile
             copiedfiles = []
-            def overridecopyfile(src, dest, *args, **kwargs):
+        def overridecopyfile(orig, src, dest, *args, **kwargs):
                 if (lfutil.shortname in src and
                     dest.startswith(repo.wjoin(lfutil.shortname))):
                     destlfile = dest.replace(lfutil.shortname, '')
@@ -697,12 +695,9 b' def overridecopy(orig, ui, repo, pats, o'
                         raise IOError('',
                             _('destination largefile already exists'))
                 copiedfiles.append((src, dest))
-                origcopyfile(src, dest, *args, **kwargs)
-
-            util.copyfile = overridecopyfile
+            orig(src, dest, *args, **kwargs)
+        with extensions.wrappedfunction(util, 'copyfile', overridecopyfile):
             result += orig(ui, repo, listpats, opts, rename)
-        finally:
-            util.copyfile = origcopyfile
 
         lfdirstate = lfutil.openlfdirstate(ui, repo)
         for (src, dest) in copiedfiles: