[bugfix] NullPointerException in UserDefinedFunction due to call == null.
[bugfix] NullPointerException in UserDefinedFunction due to call == null.

svn path=/trunk/eXist/; revision=12713

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