Keystore 2.0: Add permissions and policy for user manager AIDL.

Bug: 176123105
Test: User can set a password and unlock the phone.
Change-Id: I96c033328eb360413e82e82c0c69210dea2ddac9
diff --git a/private/system_server.te b/private/system_server.te
index e1919e2..a3e1f97 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -824,6 +824,7 @@
 allow system_server storaged_service:service_manager find;
 allow system_server surfaceflinger_service:service_manager find;
 allow system_server update_engine_service:service_manager find;
+allow system_server usermanager_service:service_manager find;
 allow system_server vold_service:service_manager find;
 allow system_server wifinl80211_service:service_manager find;
 userdebug_or_eng(`
@@ -855,7 +856,10 @@
 
 allow system_server keystore:keystore2 {
 	add_auth
+	change_password
+	change_user
 	clear_ns
+	clear_uid
 	get_state
 	lock
 	reset