Fix/img reg nohup

Created by: garloff

In upload_capi_image.sh, the openstack client is run in the background for the image registration process, as it can take a long time and we want to proceed with other things in parallel. When this is used during the initial creation of the cluster management host (with terraform), the ssh connection from terraform might end prior to the openstack client having completed the registration and upload. The ssh connection end results in a SIGHUP to the started processes and thus can result in killing the openstack client during the upload. This results in the image staying in the queued state and never turning to active. Using nohup resolves this issue.

This fixes issue #206 (closed). Should be added to v3.x and v3.0.x.

Signed-off-by: Kurt Garloff kurt@garloff.de