On RHEL 8, stunnel used to support the NO_TLSv1.1, NO_TLSv1.2, and
NO_TLSv1.3 values for the options directive. Since we do not break
compatibility, preserve these options for customers that have them set.
Resolves: RHEL-2340
Signed-off-by: Clemens Lang <cllang@redhat.com>
