LU-835 build: skip generated files in .gitignore

Skip files automatically generated during builds on FC-13.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I1cff9a351137145bb87a89460d0a1b54fae29e2c
Reviewed-on: http://review.whamcloud.com/1681


Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>