v3.trusts.update() should raise a MethodNotImplemented error (not HttpNotImplemented)

[Rodrigo Duarte]

The client method should raise a Client error and be consistent with another Managers, like RoleAssignmentsManager: https://github.com/openstack/python-keystoneclient/blob/master/keystoneclient/v3/role_assignments.py#L94

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/97355

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/97355
Committed: https://git.openstack.org/cgit/openstack/python-keystoneclient/commit/?id=53a175e7c6aca860f9a9eaa4af6d9801d0cfdba4
Submitter: Jenkins
Branch: master

commit 53a175e7c6aca860f9a9eaa4af6d9801d0cfdba4
Author: Rodrigo Duarte Sousa <email address hidden>
Date: Mon Jun 2 18:44:59 2014 -0300

    Changes exception raised by v3.trusts.update()

    The client should raise a Client error, instead of
    a Server one.

    The MethodNotImplemented exeception handles calls
    made to not supported methods.

    Change-Id: I0e2a8c5e1e53b0f17b886aa693c922bc193bb882
    Closes-Bug: #1325755