[FIO] Wrapper needs to loosen up its interpretation of "block device"

[malucius-rh]

Fio-wrapper currently checks the disk list it's fed to make sure that each device shows up as "block special." This doesn't leave room for thinks like stripesets, multipath aliases, and other things which end up as symlinks to block devices in /dev/mapper. E.g: /dev/mapper/msa1 -> /dev/dm-24 . Complicating this is that from one installation to another the dm-number to which /dev/mapper/msa1 ends up pointing can change, so simply putting /dev/dm-24 in the local_config/.config can be destructive if the user forgets to triple check the mappings.

Suggest changing "Is it a block special? If yes run if not don't run" to "Is it a block special or a symlink to one? If yes run if not don't run."