Merge branch 'jenkins-integration-fix' into 'master'

Added class to self when calling a post method.

This is a very small change to fixes https://gitlab.com/gitlab-org/gitlab-ee/issues/160 by prepending `class`to the `post` method. 

See merge request !106

app/models/project_services/jenkins_service.rb

@@ -46,7 +46,7 @@ class JenkinsService < CiService
   end
   def execute(data)
-    self.post(
+    self.class.post(
       hook_url,
       body: data.to_json,
       headers: {