Fix undesirable ripple effect on GalleryGridView

Set focusableInTouchMode = ture for workaround.

Test: Long-press a media and release it on GalleryGridView, check
      whether there is any undesirable ripple effect or not.

Change-Id: I076c47338d11b396210648a68ae393761d334c03
Signed-off-by: Taesu Lee <taesu82.lee@samsung.com>

res/layout/gallery_grid_item_view.xml

@@ -85,6 +85,7 @@
     <View
         android:layout_width="match_parent"
         android:layout_height="match_parent"
+        android:focusableInTouchMode="true"
         android:background="@drawable/gallery_image_background_selector" />
 
     <CheckBox