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
Maniphest Tasks: T11044, T11916
Differential Revision: https://secure.phabricator.com/D16924