Fix full backup/restore detection of encrypted devices

The confirmation UI did not request the needed permission, so was failing
to communicate with the mount service; as a "safe" failure mode, it was
assuming the device was encrypted.  Fixed; now it presents the correct
prompt text for the device's encryption state.

Bug 5958195

Change-Id: Ic03db16673b89d3377e0362a09cf51bfb572d78b
diff --git a/packages/BackupRestoreConfirmation/AndroidManifest.xml b/packages/BackupRestoreConfirmation/AndroidManifest.xml
index f3feee8..4fb26ae 100644
--- a/packages/BackupRestoreConfirmation/AndroidManifest.xml
+++ b/packages/BackupRestoreConfirmation/AndroidManifest.xml
@@ -19,6 +19,7 @@
     package="com.android.backupconfirm" >
 
     <uses-permission android:name="android.permission.BACKUP" />
+    <uses-permission android:name="android.permission.CRYPT_KEEPER" />
 
     <application android:allowClearUserData="false"
                  android:allowBackup="false"