revert SHOW_ON_UPGRADE removal

src/main/java/com/owncloud/android/features/FeatureList.java

@@ -36,6 +36,7 @@ import java.util.List;
  */
 public class FeatureList {
     private static final boolean SHOW_ON_FIRST_RUN = true;
+    private static final boolean SHOW_ON_UPGRADE = false;
 
     private static final int VERSION_1_0_0 = 10000099;
     private static final int VERSION_3_0_0 = 30000099;