Previous code was incorrectly assuming that the repo name always matched the host name.

Bug: chromium:1298922
Change-Id: Ic90ed585503d721f4d771b4f390a04c7f5b26622
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3507359Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Ravi Mistry <rmistry@chromium.org>