Found while testing new IML integration with Lustre RA.

When using the Lustre RA, we are currently required to pass in the realpath of devices.

This is causing an issue with a mpath device that has a realpath of /dev/dm-2.

When the Lustre RA does a monitor check it executes the following:

findmnt -t lustre -ln -o SOURCE -T $(realpath "/mnt/MGS")

This returns /dev/mapper/mpatha which is reflected in /etc/mtab.

This return is then compared against /dev/dm-2, which then states the target is not mounted, even though it is.

The Lustre RA should be able to handle any symlinked path known by Udev, and be able to normalize that to a realpath only when needed for comparison.