Don't try to solr index form-feed characters
Don't try to solr index form-feed characters

This makes sure we don't try to solr index form-feed characters. The
same has been done for vertical-tab characters in
c588a8bd6d96252325eadd6ee87e1dcc073087fc.

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