Force maintain_sb connection to use UTF-8

Currently we allow MySQLdb (our Python MySQL client) to initiate connections using its own default encoding, which on my computer is `'utf8'` but on some other devs' computers and on the server at cyder.nws.o.e is `'latin-1'`. We haven't discovered the reason for this discrepancy, so the best solution at the moment is to force the character set to be `'utf8'`. With UTF-8, I don't believe we have to do any encoding or decoding, since text-like data is returned by MySQLdb as Python unicode strings.

---

***This pull request, if merged, will require a Maintain migration.***