Fix bug causing all jobs to be deleted
Fix bug causing all jobs to be deleted

Fixes bug introduced by change
Id465078da2a7016fd59407516fe124602abd016c causing all jobs to be
unintentionally deleted on update.

The builder.delete_old_managed()'s keep parameter was expected a
string list of job names but we were mistakenly passing in a list
of XmlJob objects.

Change-Id: I4051925337691d4b59796d21f56cacf4152de1d4
Co-Authored-By: Kien Ha <3e36ebd6a7c89ee7d9a20a5fbbffc571f107e566@gmail.com>
Signed-off-by: Thanh Ha <09ea4d3a79c8bee41a16519f6a431f6bc0fd8d6f@linuxfoundation.org>

joostvdg/jenkins-job-builder,tamac-io/jenkins-job-builder,wsoula/jenkins-job-builder,dataxu/jenkins-job-builder,twc-openstack/jenkins-job-builder,phinexus/jenkins-job-builder,tamac-io/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,twc-openstack/jenkins-job-builder,OSSystems/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,phinexus/jenkins-job-builder,gforcada/jenkins-job-builder,phinexus/jenkins-job-builder,onshape/jenkins-job-builder,OSSystems/jenkins-job-builder,puppetlabs/jenkins-job-builder,gforcada/jenkins-job-builder,puppetlabs/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,tamac-io/jenkins-job-builder,gforcada/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,wsoula/jenkins-job-builder,rsig/jenkins-job-builder,rsig/jenkins-job-builder,twc-openstack/jenkins-job-builder,puppetlabs/jenkins-job-builder,dataxu/jenkins-job-builder,twc-openstack/jenkins-job-builder,joostvdg/jenkins-job-builder,tamac-io/jenkins-job-builder,phinexus/jenkins-job-builder,puppetlabs/jenkins-job-builder,rsig/jenkins-job-builder,rsig/jenkins-job-builder,OSSystems/jenkins-job-builder,onshape/jenkins-job-builder,phinexus/jenkins-job-builder,dataxu/jenkins-job-builder,gforcada/jenkins-job-builder,wsoula/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,wsoula/jenkins-job-builder,joostvdg/jenkins-job-builder,joostvdg/jenkins-job-builder,dataxu/jenkins-job-builder,onshape/jenkins-job-builder,onshape/jenkins-job-builder,gforcada/jenkins-job-builder,OSSystems/jenkins-job-builder