qemu.tests.cfg: Disable physical_resources_check for pci_assignable

We don't need to test physical_resources_check for pci_assignable,
so diable it.

Signed-off-by: Shuping Cui <scui@redhat.com>
Merge pull request #120 from spcui/physical_resources_check

qemu.tests.cfg: Disable physical_resources_check for pci_assignable