fix branches damaged by non-preservation of git.db files

[Michael Hudson-Doyle]

This is more of a task than a defect.

A bunch of git imports failed (after a successful initial import) for reasons that can be ameliorated by preserving the git.db file.

We now preserve this file, but the existing imports don't have one. The easiest way to fix them is to delete the branch data we have for these imports currently.

I'll work with Steve tomorrow to get this done.

[Michael Hudson-Doyle (mwhudson)]

I think this is all done now, but we need to verify the fix for samba.

(That import takes a while!)