Always close src/dst sessions and raise to retry
Always close src/dst sessions and raise to retry

When something goes awry for the image upload process,
always ensure the sessions are getting closed, something gets
logged and whenever necessary, an exception is re-raised for the future
retries with tenacity wrappers.

Change-Id: Id0602b0f51d4376b94e0bf5ae4e7fb34f085ed6c
Related-Bug: #1844446
Signed-off-by: Bogdan Dobrelya <a2228ae37d00d1cbd5a93e53f3e1e5aef21d5900@redhat.com>

openstack/tripleo-common,openstack/tripleo-common