fix https://github.com/sagemathinc/smc/issues/980 -- shockingly easy  -- smc.clear doesn't work robustly
fix https://github.com/sagemathinc/smc/issues/980 -- shockingly easy  -- smc.clear doesn't work robustly

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