Interesting, I am using a similar convention, but for GitHub issue labels, not commit messages [1]. Then, the commit messages often just refer to the issue number as a reference.
[1]: http://karolis.koncevicius.lt/posts/improving_github_issue_l...
[1]: http://karolis.koncevicius.lt/posts/improving_github_issue_l...
Please do not skip writing a meaningful commit message (explaining the why) because an issue number is referenced.
At a previous job all commits referenced issue numbers of a dead issue tracker no one had access to anymore, rendering git blame useless.