wireprotoserver: add version to SSH protocol names (API)

We recently introduced version 2 of the SSH protocol. Like we
did for the peer, we will need to differentiate version 1 and 2
of the server. So, we add version components to the advertised
name of the protocol handler.

Nothing in core looks for the old value. But an extension may.

.. api::

   SSH protocol handler now advertises its name internally as
   "ssh-v1" instead of "ssh."

Differential Revision: https://phab.mercurial-scm.org/D2092

mercurial/wireprotoserver.py

@@ -367,7 +367,7 b' class sshv1protocolhandler(baseprotocolh'
 
     @property
     def name(self):
-        return 'ssh'
+        return SSHV1
 
     def getargs(self, args):
         data = {}