Expect nice_err to fail on FreeBSD with unprivileged users

PR: 189821
Sponsored by: EMC / Isilon Storage Division


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273015 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Check error return from reading integer part of temperature.

There's a very remote, but possible, chance that the integer part read will
fail, but the fraction read succeeds, at which point the reported temperature is
invalid.

Reported by: Matthew Rezny
MFC after:	3 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273016 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f