Fix dict format in wait_condition.py docstrings

As mentioned in https://review.openstack.org/#/c/102888/19
there are a couple of mistakes in the docstrings, which were
unfortunately not addressed before merging, so fix now.

Change-Id: I8fbc34882b6476b75c950b16243aac43ad2a97fb
Merge "Fix dict format in wait_condition.py docstrings"