Bug 3297: Fix openSSL related build failures

Bug 3297: Fix openSSL related build failures

- The SSL_CTX_new in newer openSSL releases requires a const
'SSL_METHOD *' argument and in older releases requires non const
'SSL_METHD *' argument. Currently we are trying to identify openSSL
version using the OPENSSL_VERSION_NUMBER macro define but we are failing
to correctly identify all cases.

- sk_OPENSSL_PSTRING_value is buggy in early openSSL-1.0.0? releases
causing compile errors to squid.

This is a Measurement Factory project