MFC r208472, r208474:

MFC r208472, r208474:

MFC r208472:
Fix zfs receive temporarily changing unchanged stream properties.
Fix possible panic with zfs_enable_datasets.
OpenSolaris onnv revision: 8536:33bd5de3260e [1]

MFC r208474:
Remove kstat.zfs.arcstats.l2_write_bytes_written
The arcstats.l2_write_bytes_written kstat counter introduced
in r205231 was duplicite with vendor's arcstats.l2_write_bytes counter
imported in r208373 (OpenSolaris revision 8582:df9361868dbe)

Approved by:	pjd, delphij (mentor)
Obtained from:	OpenSolaris (Bug ID 6748561, 6757075) [1]

git-svn-id: svn://svn.freebsd.org/base/stable/8@208522 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f