Add HttpPitMinter IT

https://www.pivotaltracker.com/story/show/81483926
Instead of adding these dependencies to -kernel-impl, why not yank the HttpPidMinter out into a separate module? I'm a little worried doing this will a) give people the wrong idea about -kernel, and b) make it harder to detect accidental inclusion of HTTP-specific behavior that this level (which really, really shouldn't care about HTTP)