Description of problem:
Trying to import OVA file, failed with engine.log ERROR:
2019-03-25 14:56:35,851+02 ERROR [org.ovirt.engine.core.bll.exportimport.ExtractOvaCommand] (EE-ManagedThreadFactory-engineScheduled-Thread-16) [437ad252-1de4-47aa-9554-fa1eec
976d61] Failed to extract OVA file

and ovirt-import-ova-ansible.log:
STDOUT:

Traceback (most recent call last):
  File "/root/.ansible/tmp/ansible-tmp-1553518595.11-220475884943296/extract_ova.py", line 108, in <module>
    extract_disks(sys.argv[1], yaml.load(sys.argv[2]), yaml.load(sys.argv[3]))
  File "/root/.ansible/tmp/ansible-tmp-1553518595.11-220475884943296/extract_ova.py", line 96, in extract_disks
    image_guid = image_mappings[name] if image_mappings else name
TypeError: string indices must be integers, not str

This issue is true for RHV OVA files and VMware OVA files.
Same issue observed trying to import template as OVA.

Version-Release number of selected component (if applicable):
rhvm-4.3.2.1-0.1.el7.noarch
vdsm-4.30.11-1.el7ev.x86_64
qemu-kvm-rhev-2.12.0-21.el7.x86_64
sanlock-3.6.0-1.el7.x86_64
libvirt-client-4.5.0-10.el7_6.6.x86_64
virt-v2v-1.38.2-12.29.lp.el7ev.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Create VM.
2. Export VM as OVA.
3. Try to import OVA.

Actual results:
Import failed

Expected results:
Import should succeed.

Additional info:
engine.log, vdsm.log and ovirt-import-ova-ansible.log attached.