SSLServer::PemMemory takes a length of 0 to mean a NUL-terminated
string for cert_pem and key_pem, but skipped client_ca_pem when its
length was 0, so a server given its client CA that way started without
requiring client certificates. Read the client CA under the same rule
as the other fields. An empty client CA now fails to load instead of
turning the check off, and the README documents the length-0 rule.
yhirose
71b5f0a1c8
