River 3.0.1 Release candidate

[Peter]

Don't forget the release artifacts and signatures for the release 
candidate are
available at:
https://dist.apache.org/repos/dist/dev/river/
When we have enough people to review we can vote & release.

This is a bugfix release that addresses 
https://issues.apache.org/jira/browse/RIVER-447

Regards,

Peter.