Null pointer dereference

[abitmore]

websocketpp/websocketpp/transport/asio/connection.hpp

Lines 703 to 709 in 16d126e

	if (!m_proxy_data) {
	m_elog->write(log::elevel::library,
	"assertion failed: !m_proxy_data in asio::connection::proxy_read");
	m_proxy_data->timer->cancel();
	callback(make_error_code(error::general));
	return;
	}

On line 703 it's made sure m_proxy_data is null, but on line 706 it is dereferenced.

[zaphoyd]

@stkaufer's PR has been merged into the develop branch, fixing this.