edx/edx-platform — pull request #6212 by mlkwaqas (2014-12-10 14:16:23+00:00)
Title: Discussion categories should be sorted chronologically

By default categories should be sorted chronologically but
it is not showing result becuase of the mongo query and
use of default dict which effect the ordering. Changing
the mongo query and default dict to ordereddict fixed
the problem.

TNL-870