fix exception for discussion show no user
fix exception for discussion show no user

HadoDokis/loomio,labhackercd/loomio,juliagra/DBCloomio,HadoDokis/loomio,Collabforge/site-collabio,tachyons/loomio,tachyons/loomio,Collabforge/site-collabio,HadoDokis/loomio,doomergithub/loomio,digideskio/loomio,doomergithub/loomio,Collabforge/site-collabio,isomerase/loomio,loomio/loomio,loomio/loomio,juliagra/DBCloomio,kimihito/loomio,sicambria/loomio,isomerase/loomio,mlarghydracept/loomio,aca13jmf/loomio,juliagra/DBCloomio,loomio/loomio,juliagra/loomio,gvalerin/loomio,HadoDokis/loomio,labhackercd/loomio,mlarghydracept/loomio,isomerase/loomio,digideskio/loomio,labhackercd/loomio,sicambria/loomio,mhjb/loomio,loomio/loomio,FSFTN/Loomio,annewchen/loomio,piratas-ar/loomio,wangjun/loomio,annewchen/loomio,mlarghydracept/loomio,wangjun/loomio,kimihito/loomio,tachyons/loomio,Collabforge/site-collabio,FSFTN/Loomio,juliagra/loomio,isomerase/loomio,tachyons/loomio,codingnutty/loomio,codingnutty/loomio,kimihito/loomio,piratas-ar/loomio,piratas-ar/loomio,FSFTN/Loomio,piratas-ar/loomio,mhjb/loomio,sicambria/loomio,sicambria/loomio,labhackercd/loomio,mhjb/loomio,digideskio/loomio,annewchen/loomio,gvalerin/loomio,gvalerin/loomio,FSFTN/Loomio,juliagra/loomio,aca13jmf/loomio,aca13jmf/loomio,codingnutty/loomio,mhjb/loomio,wangjun/loomio,doomergithub/loomio