removing narrow button class as it's now a mixin

opentech/templates/base.html

@@ -119,7 +119,7 @@
                 </section>
 
                 <div class="header__button-container">
-                    <a href="#" class="button button--transparent button--narrow button--contains-icons">
+                    <a href="#" class="button button--transparent button--contains-icons">
                         <svg class="icon icon--person"><use xlink:href="#person-icon"></use></svg>
                         Log in
                     </a>