Summary:
1) Add sync status
2) Combine sync status and phab status to use one unified conduit call,
i.e. differential.querydiffhashes
Test Plan:
cd hg-crew
make local
cd ../fb-hgext
make local
cd tests
../../hg-crew/tests/run-tests.py test-phabstatus.t
../../hg-crew/tests/run-tests.py test-syncstatus.t
Reviewers: wqfish, lcharignon, #sourcecontrol, wez, ttung, rmcelroy
Reviewed By: rmcelroy
Subscribers: rmcelroy, mjpieters
Differential Revision: https://phabricator.intern.facebook.com/D3651915
Tasks: 10100400
Signature: t1:3651915:1470340328:bf003006f6afe9b86a40f204e150e0d12350c21d
