Avoid UnmappedInstanceError if c.user is None
Avoid UnmappedInstanceError if c.user is None

Addendum to afa02732f672af01ef33dbaa1520beabdf577256

alkadis/vcv,phihag/adhocracy,alkadis/vcv,liqd/adhocracy,DanielNeugebauer/adhocracy,phihag/adhocracy,phihag/adhocracy,liqd/adhocracy,SysTheron/adhocracy,DanielNeugebauer/adhocracy,liqd/adhocracy,phihag/adhocracy,phihag/adhocracy,SysTheron/adhocracy,DanielNeugebauer/adhocracy,DanielNeugebauer/adhocracy,alkadis/vcv,liqd/adhocracy,alkadis/vcv,DanielNeugebauer/adhocracy,SysTheron/adhocracy,alkadis/vcv