testlib.py: Add more logging job_completion
testlib.py: Add more logging job_completion

When this error occurs it's good to know the specific
reason.

Signed-off-by: Tony Asleson <1ef2d381aa56d512126ddaacc29e68136e4fdf55@redhat.com>

tasleson/lsm-ci,tasleson/lsm-ci