[bugfix] Fixed NPE when returning error message from XQueryServlet.
[bugfix] Fixed NPE when returning error message from XQueryServlet.

svn path=/trunk/eXist/; revision=16220

olvidalo/exist,dizzzz/exist,MjAbuz/exist,jessealama/exist,eXist-db/exist,RemiKoutcherawy/exist,kohsah/exist,patczar/exist,hungerburg/exist,dizzzz/exist,kohsah/exist,joewiz/exist,opax/exist,hungerburg/exist,wshager/exist,patczar/exist,windauer/exist,lcahlander/exist,wolfgangmm/exist,eXist-db/exist,olvidalo/exist,ambs/exist,RemiKoutcherawy/exist,lcahlander/exist,jessealama/exist,eXist-db/exist,jensopetersen/exist,jessealama/exist,patczar/exist,ambs/exist,joewiz/exist,joewiz/exist,lcahlander/exist,olvidalo/exist,joewiz/exist,MjAbuz/exist,RemiKoutcherawy/exist,hungerburg/exist,zwobit/exist,windauer/exist,adamretter/exist,dizzzz/exist,eXist-db/exist,jensopetersen/exist,lcahlander/exist,ambs/exist,kohsah/exist,zwobit/exist,windauer/exist,shabanovd/exist,jensopetersen/exist,opax/exist,ljo/exist,kohsah/exist,wolfgangmm/exist,ambs/exist,shabanovd/exist,wshager/exist,adamretter/exist,ljo/exist,wshager/exist,RemiKoutcherawy/exist,adamretter/exist,ambs/exist,opax/exist,patczar/exist,shabanovd/exist,jensopetersen/exist,jessealama/exist,lcahlander/exist,MjAbuz/exist,wolfgangmm/exist,kohsah/exist,ambs/exist,RemiKoutcherawy/exist,ljo/exist,olvidalo/exist,zwobit/exist,dizzzz/exist,lcahlander/exist,opax/exist,wshager/exist,RemiKoutcherawy/exist,zwobit/exist,hungerburg/exist,wolfgangmm/exist,adamretter/exist,ljo/exist,zwobit/exist,dizzzz/exist,adamretter/exist,eXist-db/exist,shabanovd/exist,MjAbuz/exist,wshager/exist,jensopetersen/exist,eXist-db/exist,zwobit/exist,windauer/exist,jessealama/exist,shabanovd/exist,windauer/exist,jensopetersen/exist,dizzzz/exist,joewiz/exist,olvidalo/exist,MjAbuz/exist,kohsah/exist,opax/exist,shabanovd/exist,ljo/exist,patczar/exist,windauer/exist,hungerburg/exist,wolfgangmm/exist,ljo/exist,wolfgangmm/exist,wshager/exist,jessealama/exist,joewiz/exist,MjAbuz/exist,patczar/exist,adamretter/exist