Fix bug in DevstackEngineTestCase.test_deploy

This patch changes a bit the test_deploy() test case in order for it not to
fail locally.

Change-Id: Ic1141b9bc5e74c6a0d588c8b3ccbce8a62487dc7
Closes-Bug: #1240693
Merge "Fix bug in DevstackEngineTestCase.test_deploy"