MFC: r261885

In sgetpwnam(), save and free pw_class like all other char members
of struct passwd.  This fixes spurious "login_getclass: unknown class"
errors.

PR:		186439
Submitted by:	UEMURA Tetsuya <t_uemura at macome.co.jp>
MFC: r261900

In chat_UpdateSet(), initialize the input buffer to prevent stale data
from previous timed out commands.

PR:		186530
Submitted by:	Alexander Zagrebin <alexz at visp.ru>
Reviewed by:	brian
MFC r261538:
Make CTL block backend return proper error code for operations unsupposed
by the underlying device.
MFC r261618:

In g_eli_crypto_hmac_init(), zero out after using the ipad buffer,
k_ipad.

Note that the two consumers in geli(4) are not affected by this
issue because the way the code is constructed and as such, we
believe there is no security impact with or without this change
with geli(4)'s usage.

Reported by:	Serge van den Boom <serge vdboom.org>
Reviewed by:	pjd
MFC r261620: MFV r261619:

4574 get_clones_stat does not call zap_count in non-debug kernel

zap_count(...) is never called in non-DEBUG kernel.
As result "count" variable is always 0, and "goto fail" is always
reached.  This means get_clones_stat function never makes up list
of clones for "clones" properties.
[automated] Merge in upstream-github/stable/9