<jenkins_create_job> Remove always-failing test, capture jenkins createItem HTTP response

This script was checking for the jenkins client config in
`data/jobs/app_name/config.xml`, but that file never gets
created. Removed that check, and also fixed the `curl` invocation so
that the HTTP response code is properly captured once more.
Merge pull request #4352 from dobbymoodge/master

Merged by openshift-bot