obexd: Fix exporting empty contacts
obexd: Fix exporting empty contacts

According to the spec only owner's contact should be present if
empty.

pkarasev3/bluez,silent-snowman/bluez,pkarasev3/bluez,ComputeCycles/bluez,silent-snowman/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,pkarasev3/bluez,ComputeCycles/bluez,silent-snowman/bluez,pkarasev3/bluez,silent-snowman/bluez,ComputeCycles/bluez