[QA] Change 'wait' method logic if no timeout is set

[Andrey Sledzinskiy]

In devops/helpers/helpers.py we have 'wait' method:
 def wait(predicate, interval=5, timeout=None):
    start_time = time.time()
    while not predicate():
        if timeout and start_time + timeout < time.time():
            raise TimeoutError("Waiting timed out")

        seconds_to_sleep = interval
        if timeout:
            seconds_to_sleep = max(
                0,
                min(seconds_to_sleep, start_time + timeout - time.time()))
        time.sleep(seconds_to_sleep)

    return timeout + start_time - time.time() if timeout else 0

If timeout wasn't set we can have situation when predicate is always False and we stuck in infinite loop - we will sleep every 5 seconds and never timed out.
Method need to be refactored

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/110673

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/110673
Committed: https://git.openstack.org/cgit/stackforge/fuel-devops/commit/?id=c85659bb4b10c79f2e9c84ad8f30d257daf67125
Submitter: Jenkins
Branch: master

commit c85659bb4b10c79f2e9c84ad8f30d257daf67125
Author: asledzinskiy <email address hidden>
Date: Wed Jul 30 18:13:36 2014 +0300

    Add default timeout to wait method to avoid
    infinite loop

    Change-Id: Iefd3db625c6b68d1ee95f121c628fe87ab64bbd2
    Closes-Bug: #1349886