do NOT immediately remove files from dev-downloads.libreoffice.org on update of externals!

[Stephan Bergmann]

On 05/19/2014 09:45 PM, Bjoern Michaelsen wrote:
> please do NOT remove files from dev-downloads when updating externals, keep
> those files around for at least 12 months! Otherwise you will break bibisect
> building hard (apart from also breaking people on local branches).
> So please keep whatever tarball was ever used in a LibreOffice build on the
> server for at least 12 months.

Where does the value 12 come from?

Stephan