Set default session consistency level to ONE
Set default session consistency level to ONE

Driver changed default CL from ONE to LOCAL_QUORUM on https://github.com/datastax/python-driver/commit/97bf563b7ec30fed5a1158d815a352b0fbd75a55
This broke some tests that expect CL=ONE, so we override the default CL (which can still be overriden on a per-session basis)

carlyeks/cassandra-dtest,blerer/cassandra-dtest,riptano/cassandra-dtest,pcmanus/cassandra-dtest,mambocab/cassandra-dtest,stef1927/cassandra-dtest,bdeggleston/cassandra-dtest,iamaleksey/cassandra-dtest,beobal/cassandra-dtest,beobal/cassandra-dtest,carlyeks/cassandra-dtest,spodkowinski/cassandra-dtest,aweisberg/cassandra-dtest,riptano/cassandra-dtest,stef1927/cassandra-dtest,bdeggleston/cassandra-dtest,snazy/cassandra-dtest,thobbs/cassandra-dtest,krummas/cassandra-dtest,krummas/cassandra-dtest,spodkowinski/cassandra-dtest,snazy/cassandra-dtest,mambocab/cassandra-dtest,thobbs/cassandra-dtest,aweisberg/cassandra-dtest,pauloricardomg/cassandra-dtest,iamaleksey/cassandra-dtest,pauloricardomg/cassandra-dtest,blerer/cassandra-dtest