High trust packages/repository doesn't work with PK interface

[Sebastian Heinlein]

The transaction needs to be simulated before the mechanism which chooses the alternative high trust package installation privilege for a transaction.

It is ok for a distro patch to call the core.Transaction._simulate() method in the pkcompat as a workaround. Software-center simulates the transaction before running it, so it is not affected by this bug.

After the quantal release a small code reorganizsation should happen which calls the core.Transaction._simulate() mehtod before core.Transaction._check_auth() instead of in core.Queue.put() though.