.gitignore the nested repos.

.gitignore the nested repos that live inside the proto/ dir of this
repo.

BUG=chromium:1041872
TEST=None

Change-Id: I10f1b1263b485ae5fa14df3c2232b3334ced09e7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/config/+/2055667
Commit-Queue: David Burger <dburger@chromium.org>
Tested-by: David Burger <dburger@chromium.org>
Reviewed-by: Andrew Lamb <andrewlamb@chromium.org>
1 file changed