Contact: Find FakePersona for uid

Fix bug for adding details to contacts with its primary-persona not
belonging to the default addressbook
app: properly set default address book after

This commit depends on folks bug 731470.

Fixed: https://bugzilla.gnome.org/show_bug.cgi?id=705888
Fixed: https://bugzilla.gnome.org/show_bug.cgi?id=686687