BUILD: ssl: fix two remaining occurrences of #if USE_OPENSSL

One was in backend.c and the other one in hlua.c. No other candidate
was found with "git grep '^#if\s*USE'". It's worth noting that 3
other such tests exist for SSL_OP_NO_{SSLv3,TLSv1_1,TLSv1_2} but
that these ones are properly set to 0 in openssl-compat.h when not
defined.

(cherry picked from commit b131049eb5ba5b0e7c02eea10ce9763da4428abe)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
2 files changed