wireproto: use decorator for the ubundle command

wireproto: use decorator for the ubundle command

--- a/mercurial/wireproto.py	Fri Mar 28 14:43:11 2014 -0700
+++ b/mercurial/wireproto.py	Fri Mar 28 14:43:30 2014 -0700
@@ -750,6 +750,7 @@
 
     return streamres(streamer(repo, entries, total_bytes))
 
+@wireprotocommand('unbundle', 'heads')
 def unbundle(repo, proto, heads):
     their_heads = decodelist(heads)
 
@@ -795,7 +796,3 @@
     finally:
         fp.close()
         os.unlink(tempname)
-
-commands.update({
-    'unbundle': (unbundle, 'heads'),
-})