Fix RemoteClient usage in scenario tests

[Eugene Nikanorov]

Some scenario tests use the following patter to work with RemoteClient:

 client = self.get_remote_client(
                 ip,
                 private_key=keypair.private_key)
 return client.ssh_client

ssh_client is directly accessed because exec_command method is not directly available in RemoteClient

In order to preserve encapsulation, RemoteClient should be improved to expose that method

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/77221

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/77221
Committed: https://git.openstack.org/cgit/openstack/tempest/commit/?id=91db24e002cf89811a58283272547b17866556b5
Submitter: Jenkins
Branch: master

commit 91db24e002cf89811a58283272547b17866556b5
Author: Elena Ezhova <email address hidden>
Date: Fri Feb 28 20:47:10 2014 +0400

    Fix RemoteClient usage in scenario tests

    Some scenario tests use the following patter to work with RemoteClient:

       client = self.get_remote_client(ip,
                                       private_key=keypair.private_key)
       return client.ssh_client

    ssh_client is directly accessed because exec_command method
    is not directly available in RemoteClient

    In order to preserve encapsulation, RemoteClient should be improved to
    expose that method.

    Change-Id: I054762d769d002b5fb45c871d85a8ca8ff294695
    Closes-Bug: #1285539