Warn the user that deleting a unit will also delete the lessons it contains. 	Change on 2015/10/01 by jorr <jorr@google.com> ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=104434132
Warn the user that deleting a unit will also delete the lessons it contains.
	Change on 2015/10/01 by jorr <jorr@google.com>
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=104434132

andela-angene/coursebuilder-core,andela-angene/coursebuilder-core,andela-angene/coursebuilder-core,andela-angene/coursebuilder-core