[LTP] [PATCH 1/1] tst_test.sh: Fix check for non-mounted device

[Petr Vorel]

Hi Cyril,

> Hi!
> > 1) unset TST_DEVICE if acquiring failed
> > 2) do not try to umount the device in this case

> Looks good, acked.
Thanks for your review, merged.

Kind regards,
Petr