[PATCH] Fix building with openssl problems

The attached patch fixes two problems

- Bug 3868: 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 define but looks that
sometimes we are failing to correctly identify the cases.

- sk_OPENSSL_PSTRING_value is buggy in early openSSL-1.0.0? releases
causing compile errors in squid. Also see the "compiling errors on
squid3 head 919" thread in squid-dev mailing list.

I tried to compile it using various openSSL versions. I hope it is OK
and fixes the above problems.