HSTS ignored on multiple requests

curl’s HSTS functionality fail when multiple URLs are requested serially.

Using its HSTS support, curl can be instructed to use HTTPS instead of using
an insecure clear-text HTTP step even when HTTP is provided in the URL. This
HSTS mechanism would however surprisingly be ignored by subsequent transfers
when done on the same command line because the state would not be properly
carried on.

Reproducible like this:

curl --hsts "" https://curl.se http://curl.se

The first URL returns HSTS information that the second URL fails to take
advantage of.