cql3: Make operator_type class non-copyable
cql3: Make operator_type class non-copyable

The operator_type class is really an enumeration, which is not supposed
to be copied.

avikivity/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla