d2aaa5529c
When pulling from intermediate registries we check zuul for artifacts of
a certain type. Unfortunately we do so blindly without checking that the
metadata field exists for the artifact. These leads to errors like:
"msg": "The conditional check 'item.metadata.type | default('') == 'container_image'' failed.
The error was: error while evaluating conditional (item.metadata.type | default('') == 'container_image'): 'dict object' has no attribute 'metadata'
http://logs.openstack.org/12/643712/1/gate/opendev-buildset-registry/1016e6e/job-output.txt.gz#_2019-03-18_19_28_39_060210
Address this by checking the metadata field prior to accessing it.
Change-Id: I02bbeddccdda836fc313eccce09e4cb0beb6262a