Fix communication between RB and RB Gateway

Review Request #9839 — Created March 27, 2018 and submitted — Latest diff uploaded

Information

rb-gateway
master
952b0d7...

Reviewers

Review Board's RB Gateway support requires POSTing to the /session API
(even though it doesn't actually post any form data -- it just passes an
Authorization header).

Also, the /repos/<repo>/path endpoint was mistakenly removed because it
does not return useful information. However, Review Board GETs this to
determine if authorization was successful, so I've added it back.

  • Ran unit tests.
  • Able to authorize in Review Board.