Make a result argument nullable
Make a result argument nullable

Since there is no .finish() method for this async function, and the result
is always NULL, the result argument should be nullable. This prevents it
spewing warnings.

pwithnall/folks,renatofilho/folks2,GNOME/folks,renatofilho/folks,renatofilho/folks,renatofilho/folks,renatofilho/folks,pwithnall/folks,GNOME/folks,renatofilho/folks2,renatofilho/folks2,renatofilho/folks2,pwithnall/folks,GNOME/folks