EE- Remove scss variables, part 2
EE version of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21169
Removes:
$gl-text-green
$gl-text-green-hover
$gl-text-red
$placeholder-text-color
$gl-link-color
$gl-text-orange
$gl-link-hover-color
$gl-gray
$gl-header-nav-hover-color
Edited by Annabel Dunstone Gray