Replacing "subdomain." prefix with empty string ""

Have recently come across your wonderful script to cure Wordpress database copies between domains.

Have one more challenge - I just need to replace "staging." subdomain in all urls mentioned in sql file (including serialized PHP objects).

So replacement is just empty string (""). My wordpress installation is multi-site, so there are multiple `subsiteX.maindomain.com` urls as well as `staging.subsiteX.maindomain.com` on staging server.

While migrating from staging to production we need to delete away the "staging." subdomain.