modifying libva (master) .gitignore

[Nicholas D Steeves]

P.S. I think I've finally gotten the hang of pushing tags disconnected
from a branch.  eg:
1. create local bpo development branch
2. prepare backport
3. tag bpo
4. git push origin tag_name

And the reason I made those mistakes with the audacious bpo is because
I understood "not on a branch" to mean not on a local branch, rather
than not on a remote branch.  If you would confirm that I did it
correctly, then in the future I can push bpos without a (remote)
jessie-backports branch.
https://github.com/sten0/libva-test/blob/debian/1.7.1-1_bpo8%2B1/debian/changelog

Thanks!
Nicholas