Let the udev queue settle before populating the devicetree. (#1049772)

In this case we open a LUKS device from the custom spoke in anaconda
and then call populate, but an LVM PV on the opened LUKS device can
take some time to get setup.
Fix partition handling across multiple processActions calls. (#1065522)

We replace the parted.Disk instances in all DiskLabel instances every
time processActions is run, so we need update the parted.Partition
instances throughout the devicetree accordingly.

Also, we have to make sure that each DiskLabel's _origPartedDisk is
updated before we update the DiskDevice's originalFormat with a new
copy of the DiskLabel.