user.eclass: default to SYSROOT rather than ROOT for repo details

We already rely on SYSROOT for PORTAGE_CONFIGROOT.  More importantly,
newer portage isn't able to find details under $ROOT that we need.
Lets get the tree green again while we figure out the next step.

BUG=chromium:1026502
TEST=CQ passes

Change-Id: If7dacb644d3eaea9af06c5b9e110b8b6fa2cc71a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/eclass-overlay/+/1925714
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed
tree: 387ad84d53e3b3f7316610c9c609e93884372124
  1. eclass/
  2. metadata/
  3. profiles/
  4. OWNERS
  5. PRESUBMIT.cfg