Add graceful handling for blank 'Updated Date' from whois.enom.com

Fixes: https://github.com/weppos/whois/issues/320
Merge pull request #1 from Shopify/handle-enom.com-blank-updated_date

Add graceful handling for blank 'Updated Date' from whois.enom.com
Allow blank Last Upateded On for yoursrs.com
Condense spec syntax.
Provide .expected files and regenerate specs.
Merge pull request #327 from Shopify/yoursrs-empty-last-updated-on

Handling whois.Yoursrs.com empty last updated on