Make specs compatible with PhantomJS versions < 2.

1. These versions of PhantomJS don't support `PATCH` requests, so we use
   a `POST` with `_method` set to `PATCH`.

app/assets/javascripts/protected_branches_access_select.js.coffee

@@ -21,10 +21,11 @@ class @ProtectedBranchesAccessSelect
     $(dropdown).find('.dropdown-toggle-text').text(selected.text)
     if @saveOnSelect
       $.ajax
-        type: "PATCH"
+        type: "POST"
         url: $(dropdown).data('url')
         dataType: "json"
         data:
+          _method: 'PATCH'
           id: $(dropdown).data('id')
           protected_branch:
             "#{$(dropdown).data('type')}": selected.id

spec/features/protected_branches_spec.rb

@@ -97,8 +97,6 @@ feature 'Projected Branches', feature: true, js: true do
         expect(ProtectedBranch.last.allowed_to_push).to eq(access_type_id)
       end
-      # This spec fails on PhantomJS versions below 2.0, which don't support `PATCH` requests.
-      # https://github.com/ariya/phantomjs/issues/11384
       it "allows updating protected branches so that #{access_type_name} can push to them" do
         visit namespace_project_protected_branches_path(project.namespace, project)
         set_protected_branch_name('master')
@@ -130,8 +128,6 @@ feature 'Projected Branches', feature: true, js: true do
         expect(ProtectedBranch.last.allowed_to_merge).to eq(access_type_id)
       end
-      # This spec fails on PhantomJS versions below 2.0, which don't support `PATCH` requests.
-      # https://github.com/ariya/phantomjs/issues/11384
       it "allows updating protected branches so that #{access_type_name} can merge to them" do
         visit namespace_project_protected_branches_path(project.namespace, project)
         set_protected_branch_name('master')