Allow adding new partitions to disks with active devices

Parted doesn't allow changing disklabel when there is an active
partition on the disk. Current implementation of
findActiveDevicesOnActionDisks doesn't allow adding new partitions
when there is an existing active (child) device other than another
partition (eg. VG). New version checks only actions that actually
changes the disklabel and checks status of formats of (child) devices
on the disk with changes.

Signed-off-by: Vojtech Trefny <vtrefny@redhat.com>

blivet/devicetree.py

@@ -329,18 +329,21 @@ def findActiveDevicesOnActionDisks(self):
         disks = []
         for action in self._actions:
             disk = None
-            if action.isDevice and isinstance(action.device, PartitionDevice):
-                disk = action.device.disk
-            elif action.isFormat and action.format.type == "disklabel":
+            if action.isFormat and action.format.type == "disklabel":
                 disk = action.device
 
             if disk is not None and disk not in disks:
                 disks.append(disk)
 
-        active = (dev for dev in self.devices
-                        if (dev.status and
-                            (not dev.isDisk and
-                             not isinstance(dev, PartitionDevice))))
+        active = []
+        for dev in self.devices:
+            if dev.status and not dev.isDisk and \
+               not isinstance(dev, PartitionDevice):
+                active.append(dev)
+
+            elif dev.format.status and not dev.isDisk:
+                active.append(dev)
+
         devices = [a.name for a in active if any(d in disks for d in a.disks)]
         return devices