Restore original class names for collapse/expand-medium

These no longer conflict with release index code so they can
be made less dumb.

Author: reosarevok

root/release/edit/tracklist.tt

@@ -285,7 +285,7 @@
     <table class="advanced-format">
       <tr>
         <td class="icon">
-          <button type="button" class="icon collapse-medium" data-click="toggleMedium" data-bind="css: { 'expand-re-medium': collapsed, 'collapse-re-medium': !collapsed() }, attr: { title: collapsed() ? '[% l('Expand medium') %]' : '[% l('Collapse medium') %]' }"></button>
+          <button type="button" class="icon collapse-medium" data-click="toggleMedium" data-bind="css: { 'expand-medium': collapsed, 'collapse-medium': !collapsed() }, attr: { title: collapsed() ? '[% l('Expand medium') %]' : '[% l('Collapse medium') %]' }"></button>
         </td>
 
         <td class="format">

root/static/styles/release-editor.less

@@ -77,11 +77,11 @@ fieldset.advanced-medium {
     &.expanded div.icon { display: block; }
 
     button {
-        &.collapse-re-medium {
+        &.collapse-medium {
             background-image: data-uri('../images/icons/collapse.png');
         }
 
-        &.expand-re-medium {
+        &.expand-medium {
             background-image: data-uri('../images/icons/expand.png');
         }