Website: Revert device-width change.

Turns out it only makes a difference if the viewport width=device-width
meta tag is used. Which might actually be a very good idea, but I don't
want to do it just yet.

[SVN r80720]

style-v2/css_0/header.css

@@ -117,7 +117,7 @@
     color: #005a9c;
 }
 
-@media (min-width: 550px) and (min-device-width: 550px) {
+@media all and (min-width: 550px) {
     .boost-common-header-notice {
         position: absolute;
         top: 10px;