When PVs are created on LVs, remove the devices file entries
for the PVs when the LVs are removed. In general, the devices
file entries should be removed with lvmdevices --deldev when
the LVs are removed (lvremove is the equivalent of detaching
a device from the system when layering PVs on LVs.)
This change is effectively an automatic lvmdevices --deldev
command that is built into lvremove when the LV has a PV on it.