Issues service ticket comment formatting

The issues service will currently post the message as follows:

{{{
Changeset rX:deadbeef20d285 :

Some message.
Fixes BCLOUD-21

}}}

Instead, it would read better if the changset line was identical to the one seen in the history view, and was after the commit message, rather than above it.

Example: http://bitbucket.org/prencher/wtforms/history/LICENSE.txt