CassandraStartup: configure log dir to point under tmp CLUSTER_DIR
CassandraStartup: configure log dir to point under tmp CLUSTER_DIR

Cassandra starts with

 -Dcassandra.logdir=/usr/share/cassandra/logs

However, we want this directory to be located under the temporary
directory defined by CLUSTER_DIR. Thus, move logs into ${CLUSTER_DIR}/logs.

Reviewed-by: Petr Kohout <c8dcaf59b63929e3057c562633db85285fafddd6@stud.fit.vutbr.cz>
Signed-off-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server