Diffviewer now switches commit ranges with a single revision

Review Request #7403 — Created June 10, 2015 and submitted — Latest diff uploaded

Information

Review Board
dvcs
e0f2fde...

Reviewers

Previously, the diffviewer would fail to show the correct diff when
there was only a single revision and the commit range changed. This
occured becuase when there was only a single revision, the way the
revision was being retrieved was causing an error. This resulted in
the page not being updated. This behaviour has now been rectified.

Verified the correct commit diff was shown when the selected commit
range changed.