- If there is a partition already (newly) created, then pass that
to the dialog so that it can use the setings previously applied
(e.g. mount point and flags).
- This avoids the case where you create or format a partition,
then click on it again to edit it and the previous settings are lost.
- Setup the lsit of flags consistently, by providing the available
and to-be-checked flags.
- In CreatePartitionDialog, assume that ~0 is all the flags.
We get the mountpoints already used by other partitions, and
disable the Ok button in the "Create new partition" dialog if
the user selects/writes a mountpoint which is already used.
We are going to do the same in the Edit partition dialog
after testing.
