remote-hg: avoid bad refs

Turns out fast-export throws bad 'reset' commands because of a behavior
in transport-helper that is not even needed.

Either way, better to ignore them, otherwise the user will get warnings
when we OK them.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>

contrib/remote-helpers/git-remote-hg

@@ -704,6 +704,9 @@ def do_export(parser):
         elif ref.startswith('refs/tags/'):
             tag = ref[len('refs/tags/'):]
             parser.repo.tag([tag], node, None, True, None, {})
+        else:
+            # transport-helper/fast-export bugs
+            continue
         print "ok %s" % ref
 
     print