BUILD: ssl: another build warning on LIBRESSL_VERSION_NUMBER

We had several warnings when building haproxy 2.5.4 with
old openssl 1.0.1e. This version of openssl is the latest
available in EOL centos 6.

  include/haproxy/openssl-compat.h:157:51: \
  warning: "LIBRESSL_VERSION_NUMBER" is not defined

This patch fixed the build. It changes the #if condition,
as done in other similar parts of openssl-compat.h.
1 file changed