www/tomcat-native: remove USE_OPENSSL_PORT and IGNORE LibreSSL

Even with LibreSSL using the OpenSSL 1.0.2 compatibility definitions,
there are numerous unreferenced symbols during linking. It doesn't seem
trivial to fix so IGNORE when SSL_DEFAULT=libressl*

This version of Tomcat also requires OpenSSL version 1.0.2 which is
not available in FreeBSD 9 base nor FreeBSD 10 base. Set IGNORE when
base SSL libraries are used for those 2 platforms.

Approved by: SSL blanket