Fix nav not working in mobile

In mobile thumbs don't disappear and dots are not present.
In Luma theme the var name is "nav" instead of "navigation" and it works as expected.

Author: slackerzz

app/design/frontend/Magento/blank/etc/view.xml

@@ -227,7 +227,7 @@
                 </var>
                 <var name="options">
                     <var name="options">
-                        <var name="navigation">dots</var>
+                        <var name="nav">dots</var>
                     </var>
                 </var>
             </var>