safehasattr: pass attribute name as string instead of bytes

This is a step toward replacing `util.safehasattr` usage with plain `hasattr`.
The builtin function behave poorly in Python2 but this was fixed in Python3.

These change are done one by one as they tend to have a small odd to trigger
puzzling breackage.

mercurial/utils/urlutil.py

@@ -233,7 +233,7 b' class url:'
         self.path = path
 
         # leave the query string escaped
-        for a in (b'user', b'passwd', b'host', b'port', b'path', b'fragment'):
+        for a in ('user', 'passwd', 'host', 'port', 'path', 'fragment'):
             v = getattr(self, a)
             if v is not None:
                 setattr(self, a, urlreq.unquote(v))