[WIP] Added Review_request_closed method to HostingService

Review Request #9576 — Created Feb. 3, 2018 and discarded — Latest diff uploaded

Information

Review Board
master

Reviewers

Added a new method to HostingService that is called when the
review_request_closed signal is sent.

Added a field to the Private Github repository fields to get the value
from an extra checkbox to enable the new options for configuring a bug
tracker.