Don't assign empty UID
Don't assign empty UID

mathstuf/vdirsyncer,hobarrera/vdirsyncer,tribut/vdirsyncer,untitaker/vdirsyncer,mathstuf/vdirsyncer,credativUK/vdirsyncer,untitaker/vdirsyncer,untitaker/vdirsyncer,hobarrera/vdirsyncer,credativUK/vdirsyncer,tribut/vdirsyncer