install-chef-suse: Improve handling of a failed run.
install-chef-suse: Improve handling of a failed run.

Run script with -e enabled, and use exit handler to output a helpful
message if the script terminated prematurely.

SUSE-Cloud/crowbar,MaximilianMeister/crowbar,rhafer/crowbar,rsalevsky/crowbar,mmnelemane/crowbar,crowbar/crowbar,aspiers/crowbar,aplanas/crowbar,dirkmueller/crowbar,nkrinner/crowbar,rsalevsky/crowbar,nkrinner/crowbar,toabctl/crowbar,vwallfahrer/crowbar,aplanas/crowbar,mmnelemane/crowbar,SUSE-Cloud/crowbar,vwallfahrer/crowbar,crowbar/crowbar,MaximilianMeister/crowbar,toabctl/crowbar,tserong/crowbar,aspiers/crowbar,tserong/crowbar,dirkmueller/crowbar,rhafer/crowbar,rhafer/crowbar