Deleting and re-adding a Platform results in collision

[Steven R. Loomis <srl@…>]

Scenario:

1. a platform is added, let's call it 'Foo'.
2. Due to misconfiguration of 'foo', a slave attempts to pick up this 'platform' and build it.
3. 'Foo' is deleted.
4. Later, an unrelated platform - let's call it 'Bar' is added.
5. Bar has the same 'number ' as Foo: admin/bitten/configs/(config)/10
6. The failed Foo build shows up as a failed Bar build, although it has nothing to do with Bar!

Solution: Don't re-use platform numbers.

Also, It would be great if platforms were shared between configs .. and then they were just enabled/disabled.

[Steven R. Loomis <srl@…>]

re the last comment about platforms: see bug #143