tests: fix test_cancel.py for 5ac310a8

This makes the XPath for finding the Cancel link a bit less fragile.
Commit 5ac310a8 reduced the number of wrapping divs.

Change-Id: If303f6f50a5287abc1dccbe842ad4fded8004c57
Merge "tests: fix test_cancel.py for 5ac310a8" into develop