Fix build with libressl

libressl removed the SSL Compression functionality (which might
be considered insecure) and thus also compress_meth.
SSL_SESSION_get_compress_id is just a stub in libressl which always
returns 0 and in openssl it returns compress_meth.

REVIEW: 121107
increased minimum cmake version

INCLUDE DESTINATION in install command was introduced only in CMake 2.8.12