SwiftFileBackend: fix caching issue
BAC-891: script to migrate images between DC

Conflicts:

	extensions/wikia/SwiftSync/classes/Hooks.php
	extensions/wikia/SwiftSync/classes/Queue.class.php
	includes/wikia/SwiftStorage.class.php
	maintenance/wikia/migrateImagesBetweenSwiftDC.php
BAC-891: sync images between DC should not work on devel environment

Conflicts:

	extensions/wikia/SwiftSync/classes/Hooks.php
Merge pull request #1832 from Wikia/release-193-swift-changes

Swift changes