mq: iterate over a copy of the command table keys (fixes issue2045).

I hope.

hgext/mq.py

@@ -2664,7 +2664,7 b' def uisetup(ui):'
     entry = extensions.wrapcommand(commands.table, 'init', mqinit)
     entry[1].extend(mqopt)
 
-    for cmd in commands.table:
+    for cmd in commands.table.keys():
         cmd = cmdutil.parsealiases(cmd)[0]
         if cmd in commands.norepo:
             continue