This commit rewrites the logic of table creation at startup of the auth
mechanism to be race proof. This is done by simply ignoring the
already_exists exception as done in system_distributed_keyspace.
The old creation logic, tested for existance of the column family and
right after called announce_new_column_family with the newly
created table schema. The problem was that it does not prevent
a race since the announcement itself is a fiber and the created table
can still be gossiped from another node, causing the announce
function to throw an already_exists exception that in turn crashes
scylla.
Message-Id: <20190306075016.28131-1-eliransin@scylladb.com>
479131259e