Set flavor id for Ironic's baremetal flavor

An existing trove bug prevents it from functioning when Nova flavors exist
with an id that is a UUID instead of an integer, causing Tempest failures.
This sets an integer ID when creating the baremetal flavor for Ironic's use.

Change-Id: Ic090f61a9a47421117dc86b640422f00f468112c
Related-bug: #1333852
Merge "Set flavor id for Ironic's baremetal flavor"