Added check for 'HTTP/1.1 302 Found'

[karbassi]

Before:

$ brew cask checklinks cloud-pull 
link check result for cloud-pull: failed
 - unexpected http response, expecting "HTTP/1.0 200 OK" or "HTTP/1.1 200 OK", got "HTTP/1.1 302 Found"

After:

$ brew cask checklinks cloud-pull 
link check result for cloud-pull: passed

[phinze]

I suppose some app distributors would like the flexibility of being able to provide a stable URL that redirects for mirrors support and stuff like that. Ideally we'd follow the redirect when checking links, but for I'm okay with this as an initial solution.