In LocalFile:
* Removed bogus rmdir() call.
* Added lock() calls to upgradeRow()/getSha1().
* Use FileRepo getFileSha1() in getSha1() rather than via FSFile.
* Made purgeThumbList()/migrateThumbFile() use FileRepo::cleanupBatch().
* A few other minor cleanups.
* w/s cleanup in recordUpload2().
In FSRepo:
* Removed deleted zone config code from constructor; useless since r107028.
In FileBackend:
* Make sure 'latest' param gets passed through via $params for some functions.
* Cleaned up doMoveInternal() to use *_Internal() functions.