wireproto: enable optional args for known() for future extensibility

Firstly, I think we should do this for all new wire commands, just
to be on the safe side. So I want to get this into the 1.9 release.

Secondly, there actually is potential here that sometimes the server
can know that the number of its nodes which can possibly still be
undecided on the client is small. It might then just send them along
directly (cutting short the end game). This, however, requires
walking the graph on the server, which can be expensive, so for the
moment we're not actually doing it.

mercurial/wireproto.py

@@ -288,7 +288,7 b' def lookup(repo, proto, key):'
         success = 0
     return "%s %s\n" % (success, r)
 
-def known(repo, proto, nodes):
+def known(repo, proto, nodes, others):
     return ''.join(b and "1" or "0" for b in repo.known(decodelist(nodes)))
 
 def pushkey(repo, proto, namespace, key, old, new):
@@ -412,7 +412,7 b' commands = {'
     'getbundle': (getbundle, '*'),
     'heads': (heads, ''),
     'hello': (hello, ''),
-    'known': (known, 'nodes'),
+    'known': (known, 'nodes *'),
     'listkeys': (listkeys, 'namespace'),
     'lookup': (lookup, 'key'),
     'pushkey': (pushkey, 'namespace key old new'),