Min-width menu flyout on desktop for verbose locales (bug 769358)

The bug happens because of the fixed-width flyout, which doesn't
allow longer menu items enough room. This fix allows those menu items
to simply stretch the flyout.

media/css/mkt/header.less

@@ -109,7 +109,7 @@
         visibility: hidden;
         top: 32px;
         right: -15px;
-        .width(3);
+        .min-width(3);
         z-index: 9001;
         &.active {
             opacity: 1;
@@ -155,7 +155,7 @@
             display: block;
             font-size: 15px;
             line-height: 35px;
-            padding: 0 15px;
+            padding: 0 35px 0 15px;
             position: relative;
             z-index: 2;
             &:after {