perf: don't try to call `util.queue` on Mercurial version before it existed

Differential Revision: https://phab.mercurial-scm.org/D6744

contrib/perf.py

@@ -149,7 +149,7 b' except (NameError, AttributeError, Impor'
     try:
         queue = pycompat.queue
     except (NameError, AttributeError, ImportError):
-        queue = util.queue
+        import Queue as queue
 
 try:
     from mercurial import logcmdutil