maintner: replace author/committer regexp with manual code

regexp was 25% of the CPU. Now it's lost in the long tail.

Change-Id: Ifc522d0690dff2e2524ec12354d3790946e5a54a
Reviewed-on: https://go-review.googlesource.com/38725
Reviewed-by: Kevin Burke <kev@inburke.com>
2 files changed