dm-ima: remove new_map from dm_ima_measure_on_device_clear

dm-ima: remove new_map from dm_ima_measure_on_device_clear

Now that two processes can't modify md->ima in
dm_ima_measure_on_device_clear() at the same time, there's no need to
track if an inactive table was actually removed. We might as well
clean it up unconditionally, on the off chance that a previous
ima measurement failed and left md->ima.inactive_table behind.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>