There are several painful issues with the initial CL. Doing a revert for now and will rework this.

Revert "Fix bug #12939786 BACK should go back into the Fragments BackStack and finally to Overview ...and then exit the Settings App"

This reverts commit 4cc95a53.

Change-Id: Iaa21d4771d0b004eff3d8e68b91b546a633d8f23