tui: Fix initialization bug

Fixes: #179

When a new partition is added with the TUI, it was defaulting to an
incorrect type of disk instead of partition.

Signed-off-by: Mark D Horn <mark.d.horn@intel.com>

tui/disk_config.go

@@ -493,6 +493,7 @@ func (page *DiskConfigPage) addDiskRow(bd *storage.BlockDevice) error {
 		addButton.OnClick(func(ev clui.Event) {
 			newPart := &storage.BlockDevice{
 				FsType:     "ext4",
+				Type:       storage.BlockDeviceTypePart,
 				MountPoint: "",
 				Size:       freeSpace,
 				Parent:     bd,