- Show the HTTPS-proxy options on CURLE_SSL_CACERT if libcurl was built
with HTTPS-proxy support.
Prior to this change those options were shown only if an HTTPS-proxy was
specified by --proxy, but that did not take into account environment
variables such as http_proxy, https_proxy, etc. Follow-up to e1187c4.
Reported-by: Nehal J Wani