Comment 22 for bug 1481536

Attached is a new revision (v4) of the patch, this time targeted to
Xenial (16.04) instead of Wily (15.10).

Changes from v3 to v4:

  * restore activate_vg() (which runs 'lvm vgscan' and 'llvm vgchange
    -a y') because Xenial's lvm2 package no longer includes udev rules
    that run those commands (as of 2.02.133-1ubuntu8)
  * improvements to log messages
  * drop to a shell if cryptsetup successfully unlocks the device but
    the unlocked device doesn't appear
  * drop to a shell if an LVM logical volume is expected but doesn't
    appear

A patched package has been uploaded to my PPA:
https://launchpad.net/~rhansen/+archive/ubuntu/bug1481536