draklive-install mounts the swap partitions of the installed system. On
machines with low memory, these will get used during installation. If
we unmount the swap partitions before draklive-install exits, there may
not be enough free memory to copy back the swapped out data, leading to
a kernel out-of-memory error. So let draklive-install-lock-storage
unmount them instead, after draklive-install has exited and freed up
some memory.

When the installer is run from the boot menu, draklive-install-lock-storage
is not used, but the swap partitions will be automatically unmounted on
reboot.

Use udisks2-inhibit if it is available and if the udisks2 daemon is running.
Fall back to udisks --inhibit (which only works for the older udisks daemon)
if not.

This prevents file/volume managers such as Thunar from auto-mounting disks
during the partitioning stage of installation, which can cause partitioning
to fail and cause the system to be installed on the wrong partition.