IT-release-on-demand-addon performs deploy even if NO_STAGING is not checked

Example : https://qa.nuxeo.org/jenkins/job/Deploy/job/IT-release-on-demand-addon/173/

And then the push task fails because the deploy has already been made and it can't override a release in nexus : https://qa.nuxeo.org/jenkins/job/Deploy/job/IT-release-on-demand-addon/batchTasks/task/Perform%20(push%20sources%20and%20deploy%20artifacts)/lastFailedRun/