Incorrect behaviour of method _check_instance_exists

[Sergey Nikitin]

This method must check instance existence in CURRENT token. But now it checks instance existence in ANY token. It happens because parameter token_only in sqlalchemy query was missed.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/203037

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/203037
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=e954acca67f6ed88ad21d93a4c1b5442fae56ce3
Submitter: Jenkins
Branch: master

commit e954acca67f6ed88ad21d93a4c1b5442fae56ce3
Author: Sergey Nikitin <email address hidden>
Date: Fri Jul 17 16:42:30 2015 +0300

    Fixed incorrect behaviour of method _check_instance_exists

    This method must check instance existence in CURRENT tenant.
    But now it checks instance existence in ANY tenant. It happens
    because parameter project_only=True in sqlalchemy query was missed.
    Also this method must check instance existance in ANY tenant
    if method was called with admin context.

    Due to new behaviour method was renamed to
    _check_instance_exists_in_project

    Tests for _check_instance_exists_in_project were added.

    Closes-Bug: #1475663

    Change-Id: Iad99a41823bb538a880b7cc67afc92cc97f09377