OPENDNSSEC-632

"ods-ksmutil zone add" when zonelist.xml.backup can't be written zone is still added to database.

Check the zonelist.xml.backup is writable before adding zones, and add error message when add zone failed.

I add test enforcer.ksmutil.zone_add_check_permission in testing/test-cases-daily.d/ and testing/test-cases.d/,

if everything is ok i can delete the testing/test-cases.d/enforcer.ksmutil.zone_add_check_permission.
sig_conf_name, input_name and output_name will be double freed here if xml_flag is set since they are freed at line 1103 also.