Use concatenation versus assignment when making policy declarations
Use concatenation versus assignment when making policy declarations

* Use concatenation versus assignment when making
  policy declarations inside BoardConfig.mk. This
  will allow sepolicy to exist in the vendor
  directory.

(cherryicked from b8318e8abfea1100558ac83693c51cd84edf7a97)

Change-Id: I0709fa4b8d6eaeac2fa11cd1b7106f459e443dc4

maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead