libcrypto: Check right value of CRYPTO_memcmp
sss_decrypt failed even though should pass because
we were checking wrong value of CRYPTO_memcmp.
Nobody noticed that because there was not a unit test :-)
Reviewed-by: Christian Heimes <cheimes@redhat.com>
(cherry picked from commit 0c2be9700d3b54db33c1a3dd5d230b34bfaceb50)