Removing unsupported branches into stable-historic.git

[Konstantin Ryabitsev]

Hi, all:

What do you think about deleting unsupported linux-x.x.y branches from the
stable/linux.git repository (perhaps by moving them into stable-historic.git).
These branches hold a lot of git objects that are now largely dead weight but
are still shipped around every time stable/linux.git is cloned.

According to my cursory tests, dropping unsupported branches would remove
1.1GB of obsolete objects, dropping the repository size from 3.5GB to 2.4GB
(sizes may vary in your tests due to compression, window size, etc). That's
1.1GB less traffic for each stable/linux.git clone.

Thoughts?

-Konstantin