Fix handling of size argument to devicelibs.lvm.thinlvcreate. (#1062223)
Fix type of block count in PartitionDevice._wipe.
Don't use float for anything.
Size.convertTo should return a Decimal.
Fix maxSize test when setting device target size.

maxSize can be 0, which means there is no max size.
Make teardownAll work regardless of flags.

Instead of making it do nothing except in installer mode, just don't call
it when it doesn't make sense to do so.
Improve handling of parted.DiskLabelCommitError slightly.

This approach is more focused in that it only deactivates devices that
actually use the disk we're trying to commit to.

This brings up something that should probably be addressed at some point:
We should consider some kind of warning when a partition table change is
scheduled on a disk with in-use partitions.
Don't activate or deactivate devices from the action classes. (#1064898)