QA:TestCases/ext4 fs on LVM LV

= Description = | ext4 fs on LVM LV

= How to test = |
 * 1) Boot the installer
 * 2) Advance to the (ddruid) partitioning screen
 * 3) Create a new (or use existing) LVM PVs
 * 4) Create an LVM LV using the PVs
 * 5) Assign a non-/boot mount point to the LVM LV, choosing ext4 fs type
 * 6) Complete installation
 * 7) Reboot into post-install system

= Expected Results = |
 * 1) installation completes successfully
 * 2) post-installation system boots
 * 3) ext4 filesystem is correctly identified and mounted using LVM LV device.