SAIC-285 generate_config does not have error_exit defined
SAIC-285 generate_config does not have error_exit defined

This patch defines error_exit function to produce correct error for
invalid user input.

SVilgelm/CloudFerry,MirantisWorkloadMobility/CloudFerry,japaniel/CloudFerry,andybondar/CloudFerry,SVilgelm/CloudFerry,MirantisWorkloadMobility/CloudFerry,roman-verchikov/CloudFerry,roman-verchikov/CloudFerry,roman-verchikov/CloudFerry,andybondar/CloudFerry,SVilgelm/CloudFerry,MirantisWorkloadMobility/CloudFerry,andybondar/CloudFerry,archyufa/CloudFerry,archyufa/CloudFerry,andybondar/CloudFerry,mgrygoriev/CloudFerry,japaniel/CloudFerry,Settis/CloudFerry,japaniel/CloudFerry,mgrygoriev/CloudFerry,MirantisWorkloadMobility/CloudFerry,mgrygoriev/CloudFerry,roman-verchikov/CloudFerry,japaniel/CloudFerry,mgrygoriev/CloudFerry,archyufa/CloudFerry,archyufa/CloudFerry,SVilgelm/CloudFerry