MFV 316855

7900 zdb shouldn't print the path of a znode at verbosity < 5

Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Alan Somers <asomers@freebsd.org>

illumos/illumos-gate@e548d2fa41d1baa06662ed9abbb8bcec86e27dd9
https://www.illumos.org/issues/7900

MFC after: 3 weeks
Sponsored by: Spectra Logic Corp