res:layout Removed unused namespace declaration.

src/main/res/layout/preview_image_fragment.xml

@@ -27,7 +27,6 @@
     android:gravity="center_horizontal"
 -->
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/top"
     android:layout_width="match_parent"
     android:layout_height="match_parent"