BUILD: ssl: fix a warning when built with openssl < 1.0.2

src/ssl_sock.c:2928:12: warning: ‘ssl_sock_is_ckch_valid’ defined but not used [-Wunused-function]
 static int ssl_sock_is_ckch_valid(struct cert_key_and_chain *ckch)

This function is only used with openssl >= 1.0.2, this patch adds a
condition to build the function.
1 file changed