e-d-s: make sure we remove GConf's configs between tests
e-d-s: make sure we remove GConf's configs between tests

When exercising GConf more than the usual, by creating multiple
address books or such, we might leave things in an inconsistent
state that might affect the tests that come afterwards.

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