python3: move from using func_name to __name__

Previously reviewed as D964, but required some fixups and therefore
seems to need a new revision.

Differential Revision: https://phab.mercurial-scm.org/D1065

mercurial/peer.py

@@ -90,7 +90,7 b' def batchable(f):'
         if not encresref:
             return encargsorres # a local result in this case
         self = args[0]
-        encresref.set(self._submitone(f.func_name, encargsorres))
+        encresref.set(self._submitone(f.__name__, encargsorres))
         return next(batchable)
     setattr(plain, 'batchable', f)
     return plain

mercurial/templater.py

@@ -427,9 +427,9 b' def runfilter(context, mapping, data):'
         sym = findsymbolicname(arg)
         if sym:
             msg = (_("template filter '%s' is not compatible with keyword '%s'")
-                   % (filt.func_name, sym))
+                   % (filt.__name__, sym))
         else:
-            msg = _("incompatible use of template filter '%s'") % filt.func_name
+            msg = _("incompatible use of template filter '%s'") % filt.__name__
         raise error.Abort(msg)
 
 def buildmap(exp, context):