py3: fix phabricator's use of json.loads() for py3.5

py3: fix phabricator's use of json.loads() for py3.5

Missed this in c340a8ac7ef3 since `loads()` takes bytes from 3.6 onwards.

Differential Revision: https://phab.mercurial-scm.org/D6961

--- a/hgext/phabricator.py	Fri Oct 04 18:18:38 2019 +0100
+++ b/hgext/phabricator.py	Fri Oct 04 18:33:54 2019 +0100
@@ -251,7 +251,8 @@
     parsed = pycompat.rapply(
         lambda x: encoding.unitolocal(x) if isinstance(x, pycompat.unicode)
         else x,
-        json.loads(body)
+        # json.loads only accepts bytes from py3.6+
+        json.loads(encoding.unifromlocal(body))
     )
     if parsed.get(b'error_code'):
         msg = (_(b'Conduit Error (%s): %s')