Ensure the individual is removed if all its persona list property is emptied
Ensure the individual is removed if all its persona list property is emptied

This was already the case when existing personas were removed from the
individual due to their source going away. This commit fixes it for when the
persona list property is changed directly.

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