Fix tiny nav bar back icon

Change-Id: I4ae9b3abc779ad2db03f92998c63acb74db2a0e1
AOKP custom system animations (1/2)

Ported from here: http://gerrit.aokp.co/#/c/12304/

Thanks to Steve Spear

Change-Id: I38bc7b83edaff3c455f0dfe3ea5ede54a20ae07c