Don't bother replicating to formey anymore

We did this to act as a Gerrit slave during initial setup, but
nowadays this isn't really necessary since we've got amanda
backups, plus replication of everything to Jenkins, Gitblit and
Github.

If manganese were to explode, we'd want to swap to another box
in eqiad anyway (probably antimony).

Change-Id: Ie4501c4055c06cdf869d77f6c48bb85d2c330550
Merge "Don't bother replicating to formey anymore" into production