Check for unit existence for Add Lesson button. 	Change on 2013/06/28 by juliaoh <juliaoh@google.com> ------------- Created by MOE: http://code.google.com/p/moe-java MOE_MIGRATED_REVID=48711218
Check for unit existence for Add Lesson button.
	Change on 2013/06/28 by juliaoh <juliaoh@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=48711218

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