Align build-slave-{8-10} sub-jobs to the master job

Align shell commands of https://qa.nuxeo.org/jenkins/view/System/job/System/job/build-slave-images-10.10 / https://qa.nuxeo.org/jenkins/view/System/job/System/job/build-slave-images-9.10 /  https://qa.nuxeo.org/jenkins/view/System/job/System/job/build-slave-images-8.10 to the parent job : https://qa.nuxeo.org/jenkins/view/System/job/System/job/build-slave-images

Use a versionned script shell to build images in the different branches of this repo : https://github.com/nuxeo/nuxeo-ansible-jenkins/