Define Git-over-HTTP mirror URL

Allow site administrators to direct users to another HTTP server for
change download, just like they can already do with the anonymous Git
protocol.  This lets admins move read traffic over to a replicated
HTTP environment, which may be able to handle higher traffic volumes.

Change-Id: I9fce6ad3cd42c52e50ce9da6850847444a7c032c
4 files changed