Using sanitize_key in wpmu_create_blog removes "." from the domain name

[Omicron7]

This bug was introduced with the fix for #14910, changeset [16822].

Using sanitize_key on the domain of a blog in wpmu_create_blog causes the domain name to lose all . characters. This in turn causes site_url, home_url and get_blogaddress_by_id() to return an invalid url.

Example:
wpmu_create_blog('www.example.com', '/blog1/', 'Title', . . .);
creates a blog with site_url = ​http://wwwexamplecom/blog1/

[duck_]

Already reverted, see r16848