Add dependency on ca-bundle without which the HTTPS fetches fail.
Add "-x" option to force HTTP/1.1 instead of HTTP/2.0
Add a workaround for bug in libcurl <7.530 that prevents it from
working at all when built with mbedtls.

Signed-off-by: Darren Tucker <dtucker@dtucker.net>
Acked-by: Aaron Drew <aarond10@gmail.com>