flagprocessors: add a `sidedata` parameters to _processflagswrite
To read sidedata using flagprocessors, we need flag processors to store them. So
we pass this information to the flag processing layer.
Differential Revision: https://phab.mercurial-scm.org/D6815
from __future__ import absolute_importimport pkgutil__path__ = pkgutil.extend_path(__path__, __name__)