firewalld, permission_broker: add initial support for interfaces.

This is the first patch in a two-patch series. It adds support for specifying
interfaces to firewalld. The next patch will make permission_broker use this
support.

BUG=brillo:185
TEST=unit tests
TEST=platform_Firewall

Change-Id: Ic3247a20a55427e85a4fb1ff4beadb813f8e9b7c
Reviewed-on: https://chromium-review.googlesource.com/249360
Tested-by: Jorge Lucangeli Obes <[email protected]>
Reviewed-by: Zeping Qiu <[email protected]>
Commit-Queue: Jorge Lucangeli Obes <[email protected]>
4 files changed