Introduce an option to test a custom postinstall
@pijacquo and @cdevaux asked if there could be an easy way to test a custom postinstall when generating/testing environment: this MR introduces a pipeline variable CUSTOM_POSTINSTALL_BRANCH
that can be set.
If the variable is set, a job will get and extract the latest available tgz built from the g5k-postinstall
repository for the given branch, and upload it to a pipeline-specific folder in nancy:~ajenkins
.
It will also forward the appropriate postinstall url to the generation script, and tell the test script to use the custom postinstall dsc.