Ticket 49055 - Fix create_test.py issues
    
    Bug description: It is impossible to create a test case with a default
    set of instances. Also, a replications set up creation fails.
    
    Fix description: Fix the default set condition to check for default values.
    Make one common docstring for replicationa and standalone deployments.
    
    https://fedorahosted.org/389/ticket/49055
    
    Reviewed by: vashirov (Thanks!)