As the plan has been laid out in DEPRECATED. Update docs accordingly and
verify in test 1174. Now requires the option to be set to allow HTTP/0.9
responses.
Closes#4191
Added CURLOPT_HTTP09_ALLOWED and --http0.9 for this purpose.
For now, both the tool and library allow HTTP/0.9 by default.
docs/DEPRECATE.md lays out the plan for when to reverse that default: 6
months after the 7.64.0 release. The options are added already now so
that applications/scripts can start using them already now.
Fixes#2873Closes#3383