add detaches to attachment test

The current test does 2 attaches, but if there is a
problem in detach, the test will still report
success.

This change adds detaches to the test so that
any detach failures are caught.

Change-Id: I44ee6dc5cb1ca79a4729cff41e5213b358eeb399
Closes-Bug: #1709909
1 file changed