Make cancel button kill the activity

b/31019574

Change-Id: I27c7417a0bfec5ad5a9e9247f6ea8ff6c3131361
diff --git a/Settings/src/com/android/tv/settings/device/storage/UnmountActivity.java b/Settings/src/com/android/tv/settings/device/storage/UnmountActivity.java
index 1214a13..0e63a49 100644
--- a/Settings/src/com/android/tv/settings/device/storage/UnmountActivity.java
+++ b/Settings/src/com/android/tv/settings/device/storage/UnmountActivity.java
@@ -185,7 +185,9 @@
             final long id = action.getId();
 
             if (id == GuidedAction.ACTION_ID_CANCEL) {
-                getFragmentManager().popBackStack();
+                if (!getFragmentManager().popBackStackImmediate()) {
+                    getActivity().finish();
+                }
             } else if (id == ACTION_ID_UNMOUNT) {
                 ((UnmountActivity) getActivity()).onRequestUnmount();
             }