Revert django-debug-toolbar related updates on master, set version to 0.9.4
(STUD-1201)

Revert "Specific django-toolbar version (stable released) and update the panels in dev envs"

This reverts commit a465b082da3e45604f7b4ccb210ce2826e79e72d.

Revert "Updated settings for devstack django debug toolbar"

This reverts commit 30199e8a615c54640116a6c223ba90e32a6967d2.
Merge pull request #2218 from edx/adam/revert-ddt

Revert django-debug-toolbar related updates on master, set version to 0....