Fix compatible property neverallows

The current neverallow rules for compatible properties restrict
domains from write file permissions to the various property files.
This however is the wrong restriction, since only init actually writes
to these property files.  The correct restriction is to restrict 'set'
for 'property_service' as this change does.

Note there is already a restriction preventing {domain -init} from
writing to these files in domain.te.

Test: build
Change-Id: I19e13b0d084a240185d0f3f5195e54065dc20e09