Revert "Fixed a bad test in the publisher specs"

This reverts commit e71a55c36c411767883c7cfee3528878194127dc. The original commit will be reverted too.
Revert "Raises an error if exchange we mean to connect to doesn't exist"

This reverts commit 3b6c926f8c72efa6bd8e7137319d95170c56cdfb. The test is bad, and the feature outright dangerous. The drainer thread might get killed and no one would ever know. Checking for empty routing keys needs to be done in the setup.