sepolicy: move all property read to get_prop()

There are build errors are caused by tightening of the SELinux policy. The
following change necessitates this change.

All the property  reads /write are to be replaced to
set_prop( domain,  property_label)
get_prop( domain,  property_label)

Change-Id: I6ef09a8491440b64b6e77a0ad0e2bbee2c5559ff