nfs-server.service fails to start if there is a bad entry in /etc/exports file or exported mount-point does not exist.

Issue

• nfs-server service fails to start if there is a single bad entry in /etc/export file.
• nfs-server service is stopped after a service restart if there are incorrect entries in /etc/exports.

Nov 05 02:32:06 test-rhel-82.example.com systemd[1]: Starting NFS server and services...
Nov 05 02:32:06 test-rhel-82.example.com exportfs[2474]: exportfs: Failed to stat /b: No such file or directory  
Nov 05 02:32:06 test-rhel-82.example.com systemd[1]: nfs-server.service: Control process exited, code=exited status=1
Nov 05 02:32:06 test-rhel-82.example.com systemd[1]: nfs-server.service: Failed with result 'exit-code'.
Nov 05 02:32:06 test-rhel-82.example.com systemd[1]: Stopped NFS server and services.