Update released flagged apis rule

The aconfig command has been recently updated to fully specify the
output format instead of passing the keyword format (e.g., bool). This
change reflects the change in the aconfig tool.

Test: m art.module.public.api && inspect the generate released-flagged-apis-exportable.txt output
Change-Id: I620b7f34c346288ca87342448f50a0e90813304f