libweave: Remove ownership of CommandProxyInterface by CommandInstance

Future CommandProxyInterface will be in external code, we don't want
to control their life-cycle.

BUG=brillo:1245
TEST='FEATURES=test emerge-gizmo buffet'

Change-Id: Ife0fd402ee911e3caeb20570f4b4001ebeb9dc58
Reviewed-on: https://chromium-review.googlesource.com/287194
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
12 files changed
tree: f020ffc22978cdae1f7659c174dafc5e252a9dcb
  1. buffet/
  2. libweave/