Use helper method to assert on staging log lines
Use helper method to assert on staging log lines

The exact log lines that appear when we stream logs during staging is
not always guaranteed. We were making a series of assertions on the
output that were too strict, and thus the test was failing a fraction of
the time because some lines were not appearing.

This change replaces those lines with a call to
`helpers.ConfirmStagingLogs`, which was an existing helper method that
makes a more flexible assertion on the session output.

Authored-by: Reid Mitchell <15b84f3bcf1e0a1a99817cc9360cedc980d7c5b6@pivotal.io>

cloudfoundry/cli,cloudfoundry/cli,cloudfoundry/cli