org::apache::cassandra (the generated namespace name) gets confused with
apache::cassandra (the thrift runtime library namespace), either due to
changes in gcc 7 or in thrift 0.10. Either way, the problem is fixed
by changing the generated namespace to plain cassandra.
s/database/distributed<database>/ everywhere.
Use simple distribution rules: writes are broadcast, reads are local.
This causes tremendous data duplication, but will change soon.