test: Cleanup volume group in one non-destructive test

Just janking out the disk will leave debris behind in /dev.

test/verify/check-storage-mounting

@@ -428,6 +428,11 @@ class TestStorageMountingLUKS(storagelib.StorageCase):
 
         self.login_and_go("/storage")
 
+        self.addCleanup(m.execute,
+                        "umount /run/data || true;"
+                        "cryptsetup close $(cut -d' ' -f1 /etc/crypttab) || true;"
+                        "vgremove --force test 2>/dev/null || true")
+
         # Quickly make two logical volumes
         disk = self.add_ram_disk()
         b.wait_in_text("#drives", disk)