peer: when collecting method names for batch calls, bytes-ify __name__

This will explode violently if we have a non-ascii command name. That
shouldn't ever happen in core, and seems unlikely even in third-party
code. Regardless, it'll explode violently, so we can revisit things in
the future if we need to change the encoding here.

Differential Revision: https://phab.mercurial-scm.org/D1092

mercurial/peer.py

@@ -34,7 +34,9 b' class batcher(object):'
     def __getattr__(self, name):
         def call(*args, **opts):
             resref = future()
-            self.calls.append((name, args, opts, resref,))
+            # Please don't invent non-ascii method names, or you will
+            # give core hg a very sad time.
+            self.calls.append((name.encode('ascii'), args, opts, resref,))
             return resref
         return call
     def submit(self):