Fix #8353, catch error when OpenSSL not compiled with SSLv2 context.

 * Change code to fallback to testing TLSv1 (the default) instead,
   and display a message to the user that if they really wish to
   test SSLv2 handshakes that it will be necessary for them to
   recompile OpenSSL with SSLv2 support.
Merge pull request #119 from isislovecruft/fix/8353-openssl-sslv2-context

Fix #8353, catch error when OpenSSL not compiled with SSLv2 context.