The GPL does not permit us to link against the OpenSSL library. Use
LGPL for sign-file and extract-file instead.

[ The whole "openssl isn't compatible with gpl" is really just
  fear-mongering, but there's no reason not to make modsign LGPL, so
  nobody cares.  - Linus ]
Reported-by: NJulian Andres Klode <jak@jak-linux.org>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJulian Andres Klode <jak@jak-linux.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>