Revert "Merge branch 'accept_mr_btn_ci_status' into 'master'"

This reverts commit aab713c1.

app/assets/stylesheets/pages/merge_requests.scss

@@ -19,20 +19,6 @@
   .accept-merge-holder {
     .accept-action {
       display: inline-block;
-
-      .accept_merge_request {
-        &.ci-pending,
-        &.ci-running {
-          @include btn-orange;
-        }
-
-        &.ci-skipped,
-        &.ci-failed,
-        &.ci-canceled,
-        &.ci-error {
-          @include btn-red;
-        }
-      }
     }
     .accept-control {

app/views/projects/merge_requests/widget/open/_accept.html.haml

-- status_class = @merge_request.ci_commit ? " ci-#{@merge_request.ci_commit.status}" : nil
-
 = form_for [:merge, @project.namespace.becomes(Namespace), @project, @merge_request], remote: true, method: :post, html: { class: 'accept-mr-form js-requires-input' } do |f|
   = hidden_field_tag :authenticity_token, form_authenticity_token
   .accept-merge-holder.clearfix.js-toggle-container
     .accept-action
-      = f.button class: "btn btn-create accept_merge_request#{status_class}" do
+      = f.button class: "btn btn-create accept_merge_request" do
         Accept Merge Request
     - if can_remove_branch?(@merge_request.source_project, @merge_request.source_branch) && !@merge_request.for_fork?
       .accept-control.checkbox