R1:ce18a8e20820

Fix two setup issues arising from partitioning support

Summary:
Ref T11044.

- Use shorter lock names. Fixes T11916.
- These granular exceptions now always raise as a more generic "Cluster" exception, even for a single host, because there's less special code around running just one database.

Test Plan:
- Configured bad `mysql.port`, ran `bin/storage upgrade`, got a more helpful error message.
- Ran `bin/storage upgrade --trace`, saw shorter lock names.

Reviewers: chad

Reviewed By: chad…