pull: run findcommon incoming on unfiltered repo

The discovery is not yet ready for filtered repo. Pull was using filtered for
its discovery which is wrong. It worked by dumb luck because discovery mainly
use funtion that does not respect the filtering.

Trying to makes discovery work on filtered repo revealed this bug.

mercurial/localrepo.py

@@ -1665,8 +1665,8 b' class localrepository(object):'
         trname = 'pull\n' + util.hidepassword(remote.url())
         lock = self.lock()
         try:
-            tmp = discovery.findcommonincoming(self, remote, heads=heads,
-                                               force=force)
+            tmp = discovery.findcommonincoming(self.unfiltered(), remote,
+                                               heads=heads, force=force)
             common, fetch, rheads = tmp
             if not fetch:
                 self.ui.status(_("no changes found\n"))