rust: add `profiler=true` to build config

this is necessary so we can build PGO'ed binaries.

BUG=b:189222374
TEST=`rustc -Cprofile-generate=/tmp/x` in the chroot
TEST=built memd with `EXTRA_RUSTFLAGS=-Cprofile-generate=/tmp/blah`

Change-Id: I3a03e836b581fbddcd694fe673bcf216c4625054
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/2954879
Reviewed-by: Luis Lozano <llozano@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
3 files changed