Download dependencies over http, not https
Download dependencies over http, not https

libcurl bundled with cmake doesn't support https. To enable building
sysdig without libcurl installed system wide, we need to replace
the https URLs with http.

The files still have their checksums verified.

angeloc/sysdig,angeloc/sysdig,angeloc/sysdig,angeloc/sysdig,angeloc/sysdig