[BUG] `Umount.sh` script's Cleanup Logic Doesn't Recognize Non-Default VG Names

[ferricoxide]

Describe the bug

If invoking Umount.sh with the -C flag-argument and the build-target disk contains a VG other than RootVG, it may not work as expected.

Expected behavior

Using Umount.sh -C <DEVICE> results in <DEVICE> being immediately (re)usable by the DiskSetup.sh script

Deviance Description

If the build-target disk contains a VG other than RootVG, it won't find and delete the LVM2 volume-group and associated objects, leaving the named-device not immediately (re)usable by the DiskSetup.sh script