Add websocket dep & watch api support

Add code.google.com/p/go.net/websocket to deps.sh and run update.sh.

I'd like to see us get in the habit of explicitly adding dependencies in separate PRs like this. I find it really hard to review PRs that have new dependencies and new k8s code.

This should also reduce the chance that we accept a dependency we don't actually want.

(I want websocket to implement a watch API in apiserver, which I need to split out the scheduler.)