hwservicemanager is not a HAL

This removes hwservicemanager from halserverdomain, because
halserverdomain is only for domains which offer a HAL service.
hwservicemanager offers HwBinder services, but those are not HAL
services.

Test: mmm system/sepolicy
Test: Device boots, no new denials.
Bug: 36494354
Bug: 36896667
Change-Id: I002e047ee1dd98f44429ab3dfe31f66dc63a8a1c

public/hwservicemanager.te

@@ -2,9 +2,6 @@
 type hwservicemanager, domain, mlstrustedsubject;
 type hwservicemanager_exec, exec_type, file_type;
 
-# serving android.hidl.manager@1.0 and android.hidl.token@1.0
-typeattribute hwservicemanager halserverdomain;
-
 # Note that we do not use the binder_* macros here.
 # hwservicemanager provides name service (aka context manager)
 # for hwbinder.