After this patch partition UUID and partition label will be visible
in the properties dialog of the partitions.
Also these label will only be visible if the partition table is GPT
Differential Revision: https://phabricator.kde.org/D10323
dialog -- no one is going to do any resizing, after all.
to make this possible, allow creating a PartWidget() without a valid Partition
pointer and add an init() method for later setting the Partition pointer. also
take care of the Partition pointer being NULL everywhere in the class
svn path=/trunk/extragear/sysadmin/partitionmanager/; revision=1134172