bookmarks: Only emit "item removed" if actually removed
bookmarks: Only emit "item removed" if actually removed

MathieuDuponchelle/grilo-plugins,MikePetullo/grilo-plugins,GNOME/grilo-plugins,grilofw/grilo-plugins,MathieuDuponchelle/grilo-plugins,MikePetullo/grilo-plugins,MathieuDuponchelle/grilo-plugins,GNOME/grilo-plugins,grilofw/grilo-plugins,jasuarez/grilo-plugins,MikePetullo/grilo-plugins,MathieuDuponchelle/grilo-plugins,jasuarez/grilo-plugins