Default path properties not matching documentation

[Glamdring]

The documentation lists the default values for the path properties are /etc/cassandra ... https://github.com/Netflix/Priam/wiki/2.x

However, Priam.properties has them set to /mnt/cassandra and they get loaded. So, effectively, the documentation is wrong

In fact, the bigger issue here is that many of the properties are present in Priam.properties. Because of the order in PriamConfigSource it means they cannot be overridden via command-line, only via SimpleDB. So in addition to fixing the defaults in Priam.properties, I'd suggest changing the order so that command line can override