/etc/pki/tls/certs/ca-bundle.crt not found

On ubuntu/debian, this file is in /etc/ssl/certs/ca-certificates.crt. You could symlink it. The /etc/pki/ path is used on Redhat.

Simply create a ~/.curlrc file.

Then add the following lines to the file:

capath=/etc/ssl/certs/
cacert=/etc/ssl/certs/ca-certificates.crt

Feel free to adjust those paths as necessary, as different Linux distributions may use different paths.

(Worked for Ubuntu 14.04).