Use https for curl when building for linux

Author: tmandry

src/ci/docker/dist-x86_64-linux/build-curl.sh

@@ -3,9 +3,9 @@
 set -ex
 source shared.sh
 
-VERSION=7.51.0
+VERSION=7.66.0
 
-curl http://cool.haxx.se/download/curl-$VERSION.tar.bz2 | tar xjf -
+curl https://rust-lang-ci-mirrors.s3-us-west-1.amazonaws.com/rustc/curl-$VERSION.tar.xz | xz --decompress | tar xf -
 
 mkdir curl-build
 cd curl-build