Make TrustAgentService a SystemApi

Bug: 16401527
Change-Id: I6d19281600bacac7c8a29afc07c39ca1d461d23c
diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index 20a0072..b84eca2 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -1568,7 +1568,7 @@
     public static final int KEYGUARD_DISABLE_UNREDACTED_NOTIFICATIONS = 1 << 3;
 
     /**
-     * Ignore {@link TrustAgentService} state on secure keyguard screens
+     * Ignore trust agent state on secure keyguard screens
      * (e.g. PIN/Pattern/Password).
      */
     public static final int KEYGUARD_DISABLE_TRUST_AGENTS = 1 << 4;