Include group argument in calls to create_software_config

group is a mandatory argument, and was missing from some calls.

This change also adds tests which checks all arguments to
create_software_config for cloud_config and multi_part

Change-Id: I64aba8c31bfa69fa209aefb3d86adfa6313a6621
Closes-Bug: #1392327
Merge "Include group argument in calls to create_software_config"