Merge branch 'backport-service-hook-execute-arguments' into 'master'

Backport ServiceHook#execute from EE

See merge request gitlab-org/gitlab-ce!23122

app/models/hooks/service_hook.rb

@@ -5,8 +5,8 @@ class ServiceHook < WebHook
   validates :service, presence: true
 
   # rubocop: disable CodeReuse/ServiceClass
-  def execute(data)
-    WebHookService.new(self, data, 'service_hook').execute
+  def execute(data, hook_name = 'service_hook')
+    WebHookService.new(self, data, hook_name).execute
   end
   # rubocop: enable CodeReuse/ServiceClass
 end