Same purpose as de9efa3b79af7886fcf2a67b6ce97d4f96a57421
For some unclear reason, we get occasional reports from people who do
not have /usr/sbin on their PATH that the installer fails. It's a
standard part of the PATH, so I have no clue what they're doing to
remove it--but it's also fairly cheap to avoid.
3bf7a868ee