Don't overwrite an Individual's avatar with null.
Don't overwrite an Individual's avatar with null.

(unlike the previous commit, this one actually...)

Fixes: bgo#644165 - An individual's avatar shouldn't be replaced by a null
avatar

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