Add fileutils module

The federation code uses the fileutils module from oslo-incubator,
so it needs to be in openstack-common.conf otherwise it will be
removed in a sync.

Change-Id: I6da4f026e15db4aaf0e634ede869687433acce92
test_utils use jsonutils from oslo.serialization

jsonutils in oslo-incubator is deprecated so should not be used.

Change-Id: Ib4e80dd8504d4ccbd831ad15ba4235d8245474f2
Sync modules from oslo-incubator

Sync the following modules with oslo-incubator commit
2acb6502268f7cc973c2b37ee49b73de81b8b69d :

- eventlet_backdoor
- fileutils
- log
- loopingcall
- policy
- processutils
- service
- versionutils

Use mask_password from strutils.

Remove excutils, jsonutils, strutils, and timeutils since those
modules aren't used anymore.

These modules are chosen because they're easy to sync. The goal of
the next sync is to remove the rest of the deprecated modules, but
this is blocked until Keystone uses the oslo.config config generator.

Change-Id: I7a03842d800a94a7a231da2a497be8937318857d