Workaround for broken 'make sdk'

Reduce a check for obsolete module names, from error to warning.
Symptom:
  build/core/main.mk:662: *** : Module 'bluetooth-health'
    in PRODUCT_PACKAGES has nothing to install!.  Stop.

This check is likely just a warning, in Google's internal repos.

Change-Id: I02cf9e3b9b287997465fb087d47704f4dc0cb62d