Revert "If a shortened URL begins with http://, don't include it in the shortened...

Revert "If a shortened URL begins with http://, don't include it in the shortened url. Saves 7 characters, which is pretty awesome for 140 character max length notices."

This reverts commit e2848eb8621dd645fa68cb1641c0af1df5530408.

Downstream consumers of our notices (such as Friendfeed, Facebook, etc) don't have sophisticated URL detection, so a notice that reads: "check out ur1.ca/1" won't be linked. So the http:// prefix is
mandatory.