MFC: r285482
A variable was misspelled resulting in chmod executing on the installer instead of on the target chroot

PR: 191402

MFC: r285553
make /var/audit its own dataset so it is not part of the OS boot environment

PR: 199864

MFC: r285554
Set a mountpoint on the root of the pool so user-created datasets have a mountpoint to inherit

MFC: r285557
Make bsdinstall's zfsboot script align partitions to 4k/1m when the user requests it

PR: 195174

Approved by: re (gjb), brueffer
Relnotes: yes
Sponsored by: ScaleEngine Inc.