zeroconf: constant-fold a `pycompat.ispy3`

I’ve checked that both bytes and str gets passed as the `name` parameter, so
the rest of the condition is still required. Because there aren’t really any
tests for the extensions, I didn’t want to refactor it to pass a single type.

hgext/zeroconf/Zeroconf.py

@@ -292,7 +292,7 b' class DNSQuestion(DNSEntry):'
     """A DNS question entry"""
 
     def __init__(self, name, type, clazz):
-        if pycompat.ispy3 and isinstance(name, str):
+        if isinstance(name, str):
             name = name.encode('ascii')
         if not name.endswith(b".local."):
             raise NonLocalNameException(name)