Add mirror replication option for CGit client

When using the CGit client, there is currently no way to remove refs
removed from the remote (i.e. mirroring). The mirror option was added to
the JGit client in change I3aa62c58f36f0d095bff40fe03688677b6a113d3, but
it's still missing from the CGit client.

This change adds the mirror option when using the CGit client too.

Note that `--prune-tags [1] isn't set, so only tags that track remote
refs will be removed.

[1] https://www.git-scm.com/docs/git-fetch/2.25.1#Documentation/git-fetch.txt---prune-tags

Bug: Issue 40015295
Change-Id: I59b4b57a297d4d1fdc490562a8adf38ec8a1f6bd
6 files changed
tree: d82da0464f75a785725edbbb2ea9c5a93561cbdb
  1. example-setup/
  2. src/
  3. .gitignore
  4. BUILD
  5. Jenkinsfile
  6. LICENSE