Refactor: Drop legacy selectors

These are no longer needed. The classes remain where necessary for
gadgets but the CSS rules no longer need to apply to them.

Change-Id: I18afa15ddab75128463dc83c916e11436db0575a

resources/skins.vector.styles/Menu.less

@@ -14,9 +14,7 @@
 }
 
 /* Personal */
-.vector-menu,
-/* FIXME: Remove p-personal selector when cache has cleared. */
-#p-personal {
+.vector-menu {
 	// Hidden by default, but displayed by certain menus
 	// e.g. MenuPortal
 	h3 {

resources/skins.vector.styles/MenuPortal.less

@@ -1,8 +1,6 @@
 @import '../../variables.less';
 @import 'mediawiki.mixins.less';
 
-// FIXME: For cached HTML
-.portal,
 .vector-menu-portal {
 	margin: 0 @margin-end-portal  0 @margin-start-portal;
 	padding: 0.25em 0;