4347 ZPL can use dmu_tx_assign(TXG_WAIT)
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Boris Protopopov <boris.protopopov@nexenta.com>
Approved by: Dan McDonald <danmcd@nexenta.com>
	[illumos-gate merge]

commit e722410c49fe67cbf0f639cbcc288bd6cbcf7dd1
    4347 ZPL can use dmu_tx_assign(TXG_WAIT)