Fix improperly configured host


If the host in default_url_options is accidentally set with a protocol such as `:host => "http://example.com"` then the generated url will have the protocol twice `http://http://example.com` which is not what the user intended. Likely they wanted to define a host `:host => "example.com"` and a `:protocol => "http://"` but did not know the convention.

This is may not the most common problem, but when it happens it can go undetected for a while. I accidentally added `http://` out of habit recently only to find all the links in my emails were broken after deploying a demo site to production. Rather than allow this accident go undetected, we can fix the problem in line by properly setting the protocol and host.


I was able to find this related question on stack overflow: http://stackoverflow.com/questions/5878329/rails-3-devise-how-do-i-make-the-email-confirmation-links-use-secure-https-n
 where the answer was highly upvoted. 

ATP Action Mailer, Actionpack, and Railties