Ensure that hwservice_manager adds / finds make sense.

Add a neverallow rule asserting that services registered or queried
through hwservicemanager must have the attribute hwservice_manager_type.
Attempting to add or query a service which does not have that
attribute is malformed policy.

Test: compiles
Change-Id: Ib498508694f478c396f2d9273abaccbff06975e6