Make pressing 'Back' button open the drawer when in Recents root

Change-Id: I3c6cbcd3d2d003af1a6459c3bfd193ee45021882
Fixed: 27230999

packages/DocumentsUI/src/com/android/documentsui/FilesActivity.java

@@ -381,7 +381,7 @@ public class FilesActivity extends BaseActivity {
             }
 
             // Open the Close drawer if it is closed and we're at the top of a root.
-            if (size == 1) {
+            if (size <= 1) {
                 mDrawer.setOpen(true);
                 // Remember so we don't just close it again if back is pressed again.
                 mDrawerLastFiddled = System.currentTimeMillis();