gitc: delete a few more dead references

Change-Id: I1da6f2ee799c735a63ac3ca6e5abd1211af10433
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/419217


Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>