Fix utils.import_object() when trying to get an instance of a class

[Russell Bryant]

RIght now, utils.import_object('foo') is the same as utils.import_class('foo') when 'foo' is the path to a class. This should be fixed so that import_object() returns an instance of that class (like how this works in nova.utils).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/6191

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/6191
Committed: http://github.com/openstack/openstack-common/commit/4acd7829ab0857356594dce3b841f4d785cf2aa1
Submitter: Jenkins
Branch: master

commit 4acd7829ab0857356594dce3b841f4d785cf2aa1
Author: Russell Bryant <email address hidden>
Date: Tue Apr 3 17:05:37 2012 -0400

    Change behavior in utils.import_object().

    Fix bug 972859.

    Prior to this patch, utils.import_object(foo) and
    utils.import_class(foo) would return the same thing if foo was the path
    to a class. This patch changes utils.import_object() to return an
    instance of the class, instead, also allowing you to pass in arguments
    to the constructor.

    This patch also removes the odd behavior of import_object() to be able
    to also import a module. Instead, a new function import_module() has
    been added.

    Finally, the three import helpers have been moved to a new module,
    importutils.

    Change-Id: Ia2ea64c965692f8c3a29adec332dd93a83980070