Remove remaining usages of `#menu-container`

public/css/icinga/menu.less

@@ -9,12 +9,6 @@
 
 @icon-width: 1.7em; // 1.5em width + 0.2em right margin
 
-#menu-container {
-  height: 100%;
-  overflow: hidden;
-  position: relative;
-}
-
 #menu {
   background-color: @menu-bg-color;
   box-shadow: inset -.5em 0 1em rgba(0, 0, 0, .3);

public/js/icinga/behavior/navigation.js

@@ -324,7 +324,7 @@
 
         setTimeout(function() {
             try {
-                if ($hovered.is(':hover') || $('#menu-container').is(':hover')) {
+                if ($hovered.is(':hover') || $('#menu').is(':hover')) {
                     return;
                 }
             } catch(e) { /* Bypass because if IE8 */ };