What this PR does / why we need it:
Simple code and typo fixed in nfs tests. The tests in nfs are useful as an example of how to configure a NFS server and this typo was hurting code comprehension.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
none

Special notes for your reviewer:
none

Release note:

none