CM Easy Mode File Manager Navigation fixes

This patch fixes an issue where the user cannot
get back to easy mode without exiting and re-entering
the application in certain situations

Repro Steps:
1) Select "All" in the easy mode list
2) Action Bar arrow is gone, pressing back on the navbar
does not return you to easy mode

Change-Id: I5f6b47b8b69e57cffac77f7bfa24f8a75d8ff1d4
(cherry picked from commit c5c68522)