Intent to remove old builds on July 1, 2018

[cat...@mozilla.com]

As part of a project to clean out obsolete artifacts from archive.mozilla.org, we intend to remove old files from https://archive.mozilla.org/pub/b2g/ on July 1, 2018.

On July 1 we will:
* Delete all files under https://archive.mozilla.org/pub/b2g/tinderbox-builds/
* Delete everything except latest-mozilla-central* from https://archive.mozilla.org/pub/b2g/nightly/

If removing these files will seriously impact you, please reply back to me and we can hopefully find a way to preserve the files you need while still cleaning up the majority of the old builds there.

Thanks,
Chris