Update Cassandra to 1.2.4.

Too many changes upstream, see changelog at:

https://github.com/apache/cassandra/blob/cassandra-1.2.4/CHANGES.txt

pkgsrc changes:
 - simplified config file handling
 - removed pre-install time user/group creation
 - proper data and log dir handling
Merge branch 'joyent/feature/miscfix/2013Q1' into joyent/release/2013Q1
Update joyent and wip submodules