cmake: check openssl version
cmake: check openssl version

See #835 for memory leak issues with OpenSSL >= 1.1

hypnosis-i2p/i2pd,brain5lug/i2pd,hypnosis-i2p/i2pd,PurpleI2P/i2pd,brain5lug/i2pd,hypnosis-i2p/i2pd,majestrate/i2pd,PurpleI2P/i2pd,brain5lug/i2pd,PurpleI2P/i2pd,hypnosis-i2p/i2pd,majestrate/i2pd,PurpleI2P/i2pd,majestrate/i2pd,majestrate/i2pd,majestrate/i2pd,hypnosis-i2p/i2pd,brain5lug/i2pd