Description of problem:

1.   CRs are created to install SNO cluster via siteconfig
2.  Empty NMStateConfig CR is generated. This is causing issues for Image generation.  On deletion of NMStateConfig CR, Image creation and installation happens fine

Expected result:

NMstateConfig CR should not be generated empty or should not effect Image creation

Additional info:

Error - 
Failed to create image: 1 error occurred:\n\t* <nmstatectl gc> failed, errorCode 1, stderr Traceback (most recent call last):\n  File \"/usr/bin/nmstatectl\", line 11, in <module>\n    load_entry_point('nmstate==1.0.2', 'console_scripts', 'nmstatectl')()\n  File \"/usr/lib/python3.6/site-packages/nmstatectl/nmstatectl.py\", line 73, in main\n    return args.func(args)\n  File \"/usr/lib/python3.6/site-packages/nmstatectl/nmstatectl.py\", line 378, in run_gen_config\n    if statedata[0] == \"{\":\nIndexError: string index out of range\n, input yaml <>\n\n"
    reason: ImageCreationError


It seems like we don't validate an empty NMState.