ovirt-iso-uploader: fixing usage of API SDK insecure parameter

Python SDK insecure parameter simply skips hostname validation,
it still gives errors if we also pass an unmatching CA cert.

Change-Id: Ie72fbef874f595d60e0441a212329dfb07223c16
Bug-Url: https://bugzilla.redhat.com/1136768
Signed-off-by: Simone Tiraboschi <stirabos@redhat.com>