- Fix two possible overflows when testing if ELF program headers are on
  the first page:
  1. Cast uint16_t operands in a multiplication to unsigned int because
     otherwise the implicit promotion to int results in a signed
     multiplication that can overflow and the behaviour on integer
     overflow is undefined.
  2. Replace (offset + size > PAGE_SIZE) with (size > PAGE_SIZE - offset)
     because the sum may overflow.
- Use the same tests to see if the path to the interpreter is on the first
  page. There's no overflow here because size is already limited by
  MAXPATHLEN, but the compiler optimises the new tests better. Also fix an
  off-by-one error.
- Simplify tests to see if an ELF note program header is on the first page.
  This also fixes an off-by-one error.

Reviewed by:	kib
MFV r248595:

 - Integrate OpenSSL revisions
   fb092ef4fca897344daf7189526f5f26be6487ce,
   a93cc7c57333f4538cbcdedd2e961a5a38caa52d, and
   76c61a5d1adb92388f39e585e4af860a20feb9bb.

   This removes the newly added orig_len field of SSL3_RECORD and
   restored ABI.

Approved by:	benl
MFC r248493:
Plug memory leak in dsl_check_snap_cb()
This was unnoticed because the function is very rarely used.
MFC r240870 (pjd):
It is possible to recursively destroy snapshots even if the snapshot
doesn't exist on a dataset we are starting from. For example if we
have the following configuration:

	tank
	tank/foo
	tank/foo@snap
	tank/bar
	tank/bar@snap

We can execute:

	# zfs destroy -t tank@snap

eventhough tank@snap doesn't exit.

Unfortunately it is not possible to do the same with recursive rename:

	# zfs rename -r tank@snap tank@pans
	cannot open 'tank@snap': dataset does not exist

...until now. This change allows to recursively rename snapshots even if
snapshot doesn't exist on the starting dataset.

Sponsored by:	rsync.net
Merge remote-tracking branch 'upstream/stable/9' into stable/9