Diego manifest-generation changes for Locket database configuration

Eric Malm <emalm@...>

Hi, all,

If you're currently deploying the optional, experimental Locket component
in the "classic" Diego manifest (generated by the script and templates in
the diego-release repository), the Diego team is making a few required
changes to the input stubs in v1.18.0. If you're not opting into Locket
yet, or if you're doing so via the cf-deployment manifest, you can ignore
this note.

Up until now, the Locket component has used the same SQL database
configuration as the BBS component, as specified in the sql_overrides.bbs
section of the SQL configuration stub file. Locket is now graduating to its
own independent SQL database configuration in the same stub file, under
sql_overrides.locket, and when using Locket this configuration section will
be required. This change means that you will need to fill in this section
of the stub, and also gives operators the ability to specify a different
database name or even different cluster depending on their needs.

The BOSH-Lite stubs for a single-node MySQL and the CF Postgres have been
updated to specify these required parameters but still to configure Locket
to use the "diego" database that it has heretofore shared with the BBS.
These stubs will soon be updated to switch Locket to use a separate
"locket" database in the same database cluster.

If you have any questions or problems, please ask the Diego team in the
#diego channel on the CF slack, or create an issue on the diego-release
GitHub repository.

Eric Malm, CF Diego PM