Import fake cloud instead of actual one

TODO(ogelbukh): this should be changed to configurable value
Prepopulate fake cloud data with admin user and tenant
Fix dict attributes references
Fix floating ip handling in fake cloud
Fix typos in baremetal related modules
Import six and exceptions from OpenStack clients

Import six for compatibility functions.
Import exceptions from OpenStack clients to raise correct exceptions
for handling by migration functions.
Assign _info at AttrDict initialization

This allows to avoid updating _info on every change to existing object.
Add search-related arguments to list() function for compatibility

This feigns the behavior of actual OpenStack clients' list() method
with search-related parameters.
Replicate get() behavior for object's id

OpenStack clients allow to get resource by it's ID or by the resource
object itself. In the case of fake resources, we just return an object
of respective type if it is passed for get.
Better handling of arguments in Server.create()

We could get image and flavor objects as arguments to create() method
instead of their respective IDs. We must get IDs from those objects
in that case.

Handling of the network label is also improved by this commit.
Generate UUIDs for objects correctly

UUIDs were generated once on init of Resource class for a class of
objects. This caused all objects ot that class to have the same UUIID.
We need to generate unique UUID per object instance in create() instead.
Make filter parameters optional

Default behaviour is to migrate all resources of the specified type.
Remove 'all' resource class from script args

This resource class is implemented incorrectly at the moment and
is not exactly useful.
Fix exceptions handling in baremetal script
Fix typos in baremetal script
Add optional 'setup' arg to 'migrate' subcommand

Allow to create test resources in the source cloud right before
migration has started.
Remove unused imports
Merge branch 'master' into fake-cloud-backend
Added messages to exceptions
Add suspend/resume/delete functions to fake Server resource