[CMake] Unable to download older releases: Directory index no longer supported

[Martin Weber]

Hi cmake developers,

I hope some of the cmake developers will chime in here...

The download site [1] seems to have been revamped. Since then, it does no 
longer allow to download older releases.

If the devs decided to disable directory listings due to excessive download 
traffic caused by Jenkins instances, please let me know.

I am the maintainer of a Jenkins-plugin [2], that invokes cmake to generate 
the build scripts. I recently added a feature to that plugin, which downloads 
a cmake binary (.tar.gz) from cmake.org and installs it for use of jenkins 
only. This feature seems to be very useful for people that run jenkins build 
nodes under windows or Linuxes that ship with older versions of cmake (e.g. 
RHEL-7 still ships with cmake 2.8.6).
Since the revamp, the download feature fails [3].

Download traffic on cmake.org is caused by the following:

- Jenkins backend crawler [4], runs every ~10 days on the download sites and 
detects newer releases of cmake and announces new versions to plugin users.
- Jenkins slaves (aka worker nodes) that download from cmake.org. Downloads 
happen once per slave and per cmake version, but not per build [5].

It would be nice to keep the download feature working.

TIA,
	Martin

[1] http://www.cmake.org/files/
[2] https://wiki.jenkins-ci.org/display/JENKINS/cmakebuilder+Plugin
[3] https://issues.jenkins-ci.org/browse/JENKINS-31371?focusedCommentId=240827&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-240827
[4] https://github.com/jenkinsci/backend-crawler/blob/master/cmake.groovy
[5] https://github.com/jenkinsci/cmakebuilder-plugin/commit/1ed695b9c059ab5d70833f1938ecbe68d68a031b

-- 
Cd wrttn wtht vwls s mch trsr.