Show history link instead of actual link to log. Fixes #8.

[jezdez]

This is needed work around the change in chief that adds a timespamp to the log URL: mozilla/chief@41af16d

[willkg]

One of the problems we have is that our sites have very different versions of chief. The version that kitsune has uses /logs/. It's essentially a directory being served by apache with logs of all the deployments. Fjord has a more recent version of chief which I think uses /history/ (I need to check, but monsters are in my kitchen demanding I come down "RIGHT NOW!").

This PR will break kitsune's use of chief-james, but might fix it for fjord and I bet you're suggesting it because it fixes it for mdn.

Anyhow, so the problem is that we've all got different versions of chief that have different ways of doing things. Maybe we should move the logs url to settings?

[mythmon]

+1 to making this a setting.

@jezdez: I have a branch that is partially done that also does that nasty thing we talked about in which I add an html parser and go figure out the correct link.