fix typo self.id -> self.uuid

[rcmorano]

When accessing 'Test Suites' through webui and clicking 'Create new test suite' it was raising an exception beacause a SQL was malformed because of this.

I've guessed that's the correct attribute to use since it's the unique initialized.

[rcmorano]

Hi whummer,

I got an exception the first time I launched toaster when accessing to the webui section I wrote above. It got fixed when I changed that id->uuid, but maybe it was something else.

I've destroyed the PoC VM now, but I'll try to reproduce it when I have a while and let you know :)