Move DeviceAdmin APIs to android.app.admin.

Also add ability for admins to hide themselves when not in use,
a facility for admins to not allow other admins to reset
their password, and debug dumping.
diff --git a/services/java/com/android/server/PackageManagerService.java b/services/java/com/android/server/PackageManagerService.java
index 7ce9a4ce..bf2b1c7 100644
--- a/services/java/com/android/server/PackageManagerService.java
+++ b/services/java/com/android/server/PackageManagerService.java
@@ -28,9 +28,9 @@
 import org.xmlpull.v1.XmlSerializer;
 
 import android.app.ActivityManagerNative;
-import android.app.DevicePolicyManager;
 import android.app.IActivityManager;
-import android.app.IDevicePolicyManager;
+import android.app.admin.DevicePolicyManager;
+import android.app.admin.IDevicePolicyManager;
 import android.backup.IBackupManager;
 import android.content.ComponentName;
 import android.content.Context;