Larry Rosenman and Glen Barber from the FreeBSD team reported that the OSLogin feature has not been working since the last update I made to sysutils/google-compute-engine-oslogin ports package. I found out that the problem is in some modifications made by upstream in the shell script responsible to activate and deactivate the feature. I prepared the attached patch to fix it. With the patch applied in a FreeBSD 13 instance on GCE I was able to use the OSLogin feature without any problem. I also sent this same patch upstream.