Change permission guard on bindBackupAgent()

Bug: 15829193
Change-Id: I6c1c39923b7b1a9f528f97da10913cb7f2d7e8f9
diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index 0081dfc..df96eb5 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -11408,7 +11408,7 @@
     // activity manager to announce its creation.
     public boolean bindBackupAgent(ApplicationInfo app, int backupMode) {
         if (DEBUG_BACKUP) Slog.v(TAG, "bindBackupAgent: app=" + app + " mode=" + backupMode);
-        enforceCallingPermission("android.permission.BACKUP", "bindBackupAgent");
+        enforceCallingPermission("android.permission.CONFIRM_FULL_BACKUP", "bindBackupAgent");
 
         synchronized(this) {
             // !!! TODO: currently no check here that we're already bound