Otwo 3189

Replacing all links and email addresses containing `ohloh.net` with `openhub.net`. This commit only changes documentation. The functional change is being handled in OTWO-3186. This probably needs to be merged after OTWO-3186.

I can see it both ways; we can leave "ohloh.net" because this is an example of how to get an email address by generating the MD5, but updating "ohloh" to "openhub" reinforces the name change.  Let's leave the change; no harm done.