checkheads: drop now unused filtering of 'unsyncedheads'

Now that unsynced heads are no longer in the function inputs or returns, we can
simplify the code a bit.

mercurial/discovery.py

@@ -355,16 +355,15 b' def checkheads(pushop):'
                                                          allfuturecommon,
                                                          newheads)
         newhs.update(unsyncedheads)
-        unsynced = sorted(h for h in unsyncedheads if h not in discardedheads)
-        if unsynced:
-            if None in unsynced:
+        if unsyncedheads:
+            if None in unsyncedheads:
                 # old remote, no heads data
                 heads = None
-            elif len(unsynced) <= 4 or repo.ui.verbose:
-                heads = ' '.join(short(h) for h in unsynced)
+            elif len(unsyncedheads) <= 4 or repo.ui.verbose:
+                heads = ' '.join(short(h) for h in unsyncedheads)
             else:
-                heads = (' '.join(short(h) for h in unsynced[:4]) +
-                         ' ' + _("and %s others") % (len(unsynced) - 4))
+                heads = (' '.join(short(h) for h in unsyncedheads[:4]) +
+                         ' ' + _("and %s others") % (len(unsyncedheads) - 4))
             if heads is None:
                 repo.ui.status(_("remote has heads that are "
                                  "not known locally\n"))