Allow Bluetooth sys_nice and system_server setsched for Bluetooth HAL

Bluetooth needs the capability to set audio-related threads to be RT
scheduled.  Grant it sys_nice.

system_server needs to set priority for the Bluetooth HAL.  Allow it.

Bug 37518404
Test:  Play Bluetooth audio, confirm RT scheduling with systrace
Change-Id: Iaf7b85a11a51883744d72a50addfd320b6fbbc2f
diff --git a/private/system_server.te b/private/system_server.te
index 549ace6..6a11448 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -101,6 +101,7 @@
 allow system_server appdomain:process { getsched setsched };
 allow system_server audioserver:process { getsched setsched };
 allow system_server hal_audio:process { getsched setsched };
+allow system_server hal_bluetooth:process { getsched setsched };
 allow system_server cameraserver:process { getsched setsched };
 allow system_server hal_camera:process { getsched setsched };
 allow system_server mediaserver:process { getsched setsched };