COOK-4664
COOK-4664

validate_dow fails on Fixnums. Check spec.class before validating

martinb3-cookbooks/cron,chef-cookbooks/cron,chasebolt/cron,jhauf-nativex/chef-cron,erkolson/cron,evertrue/cron,jeroenj/cron,Altiscale/cron,Altiscale/cron,flaccid/cron,opscode-cookbooks/cron,jeroenj/cron,veetow/cron,opscode-cookbooks/cron,chasebolt/cron,chef-cookbooks/cron,erkolson/cron,flaccid/cron,veetow/cron