fix floating ip test that wasn't running

the associate_floating_ip negative test wasn't running because
the indent was wrong. This was uncovered when looking for unknown
names with pyflakes.

This makes the test run, and fixes the mispelling of floating to
make it actually pass.

Change-Id: I74397b8592d51a7fed249c96f17d3e71cdf82a7e
Merge "fix floating ip test that wasn't running"