package/znc: requires blowfish support in openssl

Enable blowfish in openssl to fix build failure raised since commit
a83d4186

Fixes:
 - http://autobuild.buildroot.org/results/600f2b09da919d511df87d3f19fea71149c1260c



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>