fix bug in listings where it checks the wrong condition for a table (a disconnected table can be used just fine!)
fix bug in listings where it checks the wrong condition for a table (a disconnected table can be used just fine!)

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