Applications created prior to the deployments changes in the November release do not always get the new jenkins_shell_command values when deleting and re-adding jenkins-client.

If an application was created before the November release, it most likely has a jenkins_shell_command file in $OPENSHIFT_PRIMARY_CARTRIDGE_DIR/metadata/jenkins_shell_command. This file contains the shell commands prior to the November release changes. Deleting the jenkins-client cartridge from the application does not remove this file. When re-adding jenkins-client to the application, instead of using the jenkins_shell_command file from the jenkins-client cartridge, it reuses the (now stale) file in $OPENSHIFT_PRIMARY_CARTRIDGE_DIR, so the new jenkins job does not have the newest jenkins_shell_command content.

The following logic allows cartridges to have custom jenkins_shell_commands, which is generally fine, but in situations like this, it is desirable to be able to delete files like php/metadata/jenkins_shell_command when they are no longer installed or maintained by the platform.

https://github.com/openshift/origin-server/blob/master/cartridges/openshift-origin-cartridge-jenkins-client/bin/install#L19-L25