Flavor Extra Specs should require admin privileges

The previous fix added admin check in policy.json,
but code still can't recorginize the detailed actions.

This fix edited "authorize" function for flavor_extra_specs,
to make sure it will check the admin privileges in policy.json.

Also, together with the code, this fix edit old test case with admin privileges,
and added new non-admin privileges test case.

Fixes bug 1094142

Change-Id: Ia286aedb4846383ad51bd54b0984dd1feddfbf81
Change to support custom nw filters.

This change is a refactoring of NWFilterFirewall to
create a distinct function to define base nw filters.
The new function is called get_base_filter_list.  This
provides a convenient way to subclass NWFilterFirewall
and redefine get_base_filter_list to add your own custom
base filters.

Change-Id: Ida94148fcb870830ae675839ab4f900ad798d9bb
Fixes: bug #1103086
Merge "Change to support custom nw filters."
Merge "Flavor Extra Specs should require admin privileges"