On the diff page the list of comments doesn't differenciate between

top-level comments and replies to those comments. Because reviewboard

doesn't support replying to a reply of a comment, the "Reply" link on

those reply comments would not work properly. This fix solves that problem

by changing those reply links to reply to their parent comment.

Manual Test:

-Create a comment on a line on the diff viewer page for a review request.
-Reply to that comment.
-Go back to the diff viewer page and click the reply link of 

that reply comment.
-Expected result is that it should go to the review page, scroll to, 

and open the reply editor for the parent comment of that reply.
-Jasmine js test suite passed

-Reviewboard unit test suite passed

-2 new tests added to the js test suit