ci: use https, not http to download binaries from perforce.com

Since 522354d (Add Travis CI support, 2015-11-27) the CI has used
http://filehost.perforce.com/perforce/ to download binaries from
filehost.perforce.com, they were then moved to this script in
657343a (travis-ci: move Travis CI code into dedicated scripts,
2017-09-10).

Let's use https instead for good measure. I don't think we need to
worry about the DNS or network between the GitHub CI and perforce.com
being MitM'd, but using https gives us extra validation of the payload
at least, and is one less thing to worry about when checking where
else we rely on non-TLS'd http connections.

Also, use the same download site at perforce.com for Linux and macOS
tarballs for consistency.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Carlo Marcelo Arenas Belón <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

ci/install-dependencies.sh

@@ -5,7 +5,7 @@
 
 . ${0%/*}/lib.sh
 
-P4WHENCE=http://filehost.perforce.com/perforce/r$LINUX_P4_VERSION
+P4WHENCE=https://cdist2.perforce.com/perforce/r$LINUX_P4_VERSION
 LFSWHENCE=https://github.com/github/git-lfs/releases/download/v$LINUX_GIT_LFS_VERSION
 UBUNTU_COMMON_PKGS="make libssl-dev libcurl4-openssl-dev libexpat-dev
  tcl tk gettext zlib1g-dev perl-modules liberror-perl libauthen-sasl-perl