Ultrasound: modifications for SEAndroid

1. usf_post_boot.sh script now uses "source" to call the
usf_settings.sh script. Using sh directly would run usf_settings.sh
in a new process with incorrect security context.

2. Added creation of /data/usf directory to init.target.rc so
that it would have the correct security label. In addition,
modified usf_settings.sh to correctly copy /system/etc/usf into
the now already existing /data/usf.

Change-Id: I875349a85ec55dea6a4f67ccbe388cf003ec6588
3 files changed