
Using HTTPS without root (CA) certificates is a security issue. Print a warning in this case. Also, when certificate verification fail, print an additional message because "HTTP client error 4" is not very informative (4 is HTTPC_RESULT_ERR_CLOSED). Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>