Update nav bar controller to allow for a home intent to be fired without

having a package name.

Test: After set up select the Lenspicker as the home app then click the
  home button (note: needs other commits with topic "AAE Home"

Change-Id: Ief9871bcc81902036d7af9630d6f1d27e8c83366
(cherry picked from commit Icddda312c10dfd603fb098fec13dae55d807444e)
# Conflicts:
#	packages/SystemUI/src/com/android/systemui/statusbar/car/CarNavigationBarController.java