Prezero the acl structure which is to be copied to usermode, to avoid leakage of the previous content of padding and unitialized fields.
Prezero the acl structure which is to be copied to usermode, to avoid
leakage of the previous content of padding and unitialized fields.

Reported by:	Ilia Noskov <noskov@nic.ru>
Reviewed by:	kib
MFC after:	1 week

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