fix https://github.com/sagemathinc/smc/issues/1819 -- don't re-emit primus error events
fix https://github.com/sagemathinc/smc/issues/1819 -- don't re-emit primus error events

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