NFSD: Added fault injection script

This script provides a convenient way to use the NFSD fault injection
framework.  Fault injection writes to dmesg using the KERN_INFO flag, so
this script will compare the before and after output of `dmesg` to show
the user what happened

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>