Make floating ip test work. Fixes bug 929765.

The problems were:
1. FloatingIP client does not use json/headers for POST
2. The API data for associate/disassociate floating ip were wrong
3. The negative cases were too specific about what exception would be thrown

Also made test_server_metadata work.

Change-Id: I5bea4e03203391042589ba264d9eaed3ef1199b3

Make test_flavors.py pass.

There were some "expect failures" for bugs that have been fixed in Essex.
Added release_name, defaulting to essex, to allow skipping of tests of things
that are broken in diablo but fixed in essex.

Change-Id: I38ada5ee200104efe112a3bcd12b902c63e4b9ed
5 files changed