sshpeer: remove frivolous call to _cleanup()

_validaterepo() is called once during __init__. _cleanup()
no-ops if the self._pipe* attributes aren't set. These attributes
are set during _validaterepo(). So the call to _cleanup() isn't
necessary.

But just to be on the safe side, we add an assertion.

Differential Revision: https://phab.mercurial-scm.org/D2030

mercurial/sshpeer.py

@@ -173,8 +173,7 b' class sshpeer(wireproto.wirepeer):'
     # End of _basewirecommands interface.
 
     def _validaterepo(self, sshcmd, args, remotecmd, sshenv=None):
-        # cleanup up previous run
-        self._cleanup()
+        assert self._pipei is None
 
         cmd = '%s %s %s' % (sshcmd, args,
             util.shellquote("%s -R %s serve --stdio" %