fix: overcome spatial/scipy bug where a int is returned in place of list when only one NN
fix: overcome spatial/scipy bug where a int is returned in place of list when only one NN

oscarlorentzon/OpenSfM,oscarlorentzon/OpenSfM,oscarlorentzon/OpenSfM,mapillary/OpenSfM,mapillary/OpenSfM,oscarlorentzon/OpenSfM,mapillary/OpenSfM,mapillary/OpenSfM,mapillary/OpenSfM,oscarlorentzon/OpenSfM