Clear options on the context.
void clear_options( options o, asio::error_code & ec);
This function may be used to configure the SSL options used by the context.
A bitmask of options. The available option values are defined in
the ssl::context_base
class. The specified options, if currently enabled on the context,
are cleared.
Set to indicate what error occurred, if any.
Calls SSL_CTX_clear_options
.