Remove tmp bitstream file always
Remove tmp bitstream file always

On fpga program, we will download a bitstream file from glance
to a tmp local file. And no matter driver.program is success
or failed, the tmp local file should be removed

Change-Id: Ic7be96f3f6da9cf366224401bc330485e67fedf1
Signed-off-by: guolei <caa5e50d9471c7d51411c81ac6ef400323e369a5@cmss.chinamobile.com>

openstack/nomad