Quick and insecure fix WARNING: the change disables certificate validation. Use at your own risk.
Until PycURL is fixed you can edit file /usr/lib/python2.6/dist-packages/imagestore/lib/fetch.py on fetch method after the line 142 add
curl.setopt(pycurl.SSL_VERIFYPEER, 0)
curl.setopt(pycurl.SSL_VERIFYHOST, 0)
Restart the image-store-proxy
And also update godaddy certificates:
sudo wget -P /usr/local/share/ca-certificates/ --no-check-certificate https://certs.godaddy.com/repository/gd-class2-root.crt https://certs.godaddy.com/repository/gd_intermediate.crt https://certs.godaddy.com/repository/gd_cross_intermediate.crt
sudo update-ca-certificates