build_packages: Bump backtrack to 1000

Stale binpkgs are starting to multiply, and portage at the moment
isn't appearing to figure out that some of them can't be used anymore,
likely as --backtack=30 just isn't big enough to do that.

The risk of increasing --backtrack further is that we may just hang
longer calculating dependencies (possibly past the death of the
universe), but at least we won't ever try and use binpkgs that we
can't.  If this change ends up making things worse, we can just revert
it.

BUG=b:214297402
TEST=CQ

Change-Id: I6624658cdbd8904af01eb5293f687d4cbd415d46
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3383660
Tested-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: George Engelbrecht <engeg@google.com>
Reviewed-by: Joshua Emele <jemele@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
1 file changed