heirloom-mailx: disable SSLv2 support

Now that openssl has dropped SSLv2 support from the latest security bump
we need to patch it out here as well. Fixes:
http://autobuild.buildroot.net/results/dab/dab1629cfcb5cb33706d0c762dba57baa43299a5/



Patch status: debian upstream.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>