SSLServer, SSLClient and WebSocketClient take a PemMemory with
cert_pem_len and key_pem_len, but the lengths were never read: every
backend read the PEM up to a NUL, so a buffer holding exactly the PEM,
such as a std::vector<char> read from a file, was read past its end.
Hand on a NUL-terminated copy of the given number of bytes instead.
A length of 0 still means a NUL-terminated string, which is what
callers got before. The client CA already honored its length.
yhirose
30879bb48b
