Use ro.slim.device

  * Drop ro.product.device due to its problematic with unified devices

Change-Id: I95615e2c0edc6edb34280dac5ffb57468aa56955
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>
Merge branch 'kk4.4' of https://github.com/SlimRoms/packages_apps_SlimCenter into kk4.4