libtcmu: free tcmu_device after dev->fd is closed
libtcmu: free tcmu_device after dev->fd is closed

the device fd is freed in thread cleanup function,  this fd cannot be closed since it is not a valid fd

Signed-off-by: xinxin shu <71886b11fed29c5ed22d2a096901a714e819d39f@chinac.com>

agrover/tcmu-runner,lxbsz/tcmu-runner,open-iscsi/tcmu-runner,open-iscsi/tcmu-runner,JefferyHu/tcmu-runner,liuy/tcmu-runner,superlibj/tcmu-runner