OS-2222 make reprovision more robust by forcing zfs renames and undoing transition if we fail.
OS-2223 don't fail reprovision when /zones/<uuid>/cores is not mounted.
OS-2213 switch metadata agent to using internal_metadata for *_pw keys to support older datasets.
OS-2224: imgadm "-E" option for machine parsable error
OS-2211: Set umask instead of chmod'ing, set metdata.sock smartdc directory usable only by root