Revert "build:  do not show TARGET_BUILD_APPS unless it is set"

This reverts commit bf65a5fd050416ff61a2309655dfc6658278746f.
Include privileged apps with app zip file.

Include apps that appear under /system/priv-app
to also be included with the zip of all the apps.

Change-Id: If4687cf4c471877f11d78b68bad96f1842e49d87
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>