fixes for rethinkdb 2.1
fixes for rethinkdb 2.1

sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,sagemathinc/smc