Make `bin/storage upgrade` and `bin/storage adjust` emit detailed messages if the user has no access to databases
Summary:
Ref T10195. Distinguish between "database does not exist" and "database exists, you just don't have permission to access it".
We can't easily get this information out of INFORMATION_SCHEMA but can just `SHOW TABLES IN ...` every database that looks like it's missing and then look at the error code.
Test Plan:
- Created a user `limited` with limited access.
- Ran `bin/storage adjust`.
- Got hopefully more helpful messages about access problems, instead of "Missing" errors.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T10195
Differential Revision: https://secure.phabricator.com/D15079