[Build] Deploy RelEng scripts in master branch build

[HannesWell]

This ensures that releng scripts are always updated on the download-server as soon as they change in the git repository. Furthermore this avoids the need for the separate Jenkins job to deploy the scripts, thus making
https://ci.eclipse.org/releng/job/Publish_shell_scripts_for_releng_jobs/ obsolete (can be deleted once this is submitted).

[HannesWell]

Verified that this works by replaying the verification build and modified it to deploy to:

• https://download.eclipse.org/eclipse/relengScripts2-tries/

Will delete that entire folder again, together with the https://ci.eclipse.org/releng/job/Publish_shell_scripts_for_releng_jobs/ Jenkins job, once this is submitted.

[HannesWell]

I have now added a 'staging' mechanism to minimize downtime, but I have to test this better.

[HannesWell]

With the latest adjustments and after some more testing I think this is now ready.
The result can be seen in my testing area at:

• https://download.eclipse.org/eclipse/relengScripts2-tries/relengScripts/

In general I would be nice to just start the deployment if something has changed, e.g. by uploading the commit-id of the current commit too and then running git diff before uploading, but I assume that's not worth the effort?

[akurtakov]

Please get this one in and checks can be following commits.

[HannesWell]

Please get this one in and checks can be following commits.

Yes. I just had it almost completely running quickly after my last message. So we have it with check now already. :)

Submitting now, as the verification build does not test this.

To bootstrap the state file this change I will have to Replay the master build with the modification that the git diff is skipped and the deployment happens unconditionally so that the state file is created initially.

[HannesWell]

After unanticipated build failures on the initial run on master I figured out that the disposal location download.eclipse.org/eclipse/relengScripts-disposal was created by the genie.releng and can therefore not be deleted by the genie.platform:

 drwxr-sr-x   8 genie.platform eclipse.platform  4096 Dec 12 16:24 relengScripts/
 drwxr-sr-x   7 genie.releng   eclipse.platform  4096 Dec  8 12:30 relengScripts-disposal/

Deleting download.eclipse.org/eclipse/relengScripts-disposal from the releng JIPP (that uses the genie.releng) solved the problem now and the scripts could be deployed completely successful.
I'm going to delete the Publish_shell_scripts_for_releng_jobs job from the RelEng Jenkins now. It's now obsolete.