git-codereview: fix TestCurrentBranch
git-codereview: fix TestCurrentBranch

Fixes #9379

Change-Id: Ia9122464574355c01e6c457087b0eef9375826e2
Reviewed-on: https://go-review.googlesource.com/1772
Reviewed-by: Chris Manghane <fe04d2e6759ff872548dffaa0000d96c00597e75@golang.org>

Go-zh/review,golang/review