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

Author: Christopher Tate

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"

packages/BackupRestoreConfirmation/src/com/android/backupconfirm/BackupRestoreConfirmation.java

@@ -265,6 +265,7 @@ boolean deviceIsEncrypted() {
         } catch (Exception e) {
             // If we can't talk to the mount service we have a serious problem; fail
             // "secure" i.e. assuming that the device is encrypted.
+            Slog.e(TAG, "Unable to communicate with mount service: " + e.getMessage());
             return true;
         }
     }