Dropping of DAP permission causes false alert when debugging.

BRANCH=none
BUG=chrome-os-partner:43025,chrome-os-partner:47239
TEST=ran debugger and checked for absence of bus errors
Signed-off-by: nagendra modadugu <ngm@google.com>

Change-Id: I97f3840000a271ef3402f0f3df88258f7a513d4e
Reviewed-on: https://chromium-review.googlesource.com/310542
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Commit-Queue: Nagendra Modadugu <ngm@google.com>
Trybot-Ready: Nagendra Modadugu <ngm@google.com>
Tested-by: Nagendra Modadugu <ngm@google.com>