zfs: merge OpenZFS master-891568c99
Notable upstream pull request merges:
#11652 Split dmu_zfetch() speculation and execution parts #11682 Fix zfs_get_data access to files with wrong generation #11735 Clean up RAIDZ/DRAID ereport code #11737 Initialize metaslab range trees in metaslab_init #11739 FreeBSD: make seqc asserts conditional on replay #11763 Allow setting bootfs property on pools with indirect vdevs #11767 FreeBSD: Fix memory leaks in kstats
Obtained from: OpenZFS
MFC after: 2 weeks