ublk: fail to recover device if queue setup is interrupted

In the Linux kernel, the following vulnerability has been resolved:

ublk: fail to recover device if queue setup is interrupted

In ublk_ctrl_end_recovery(), if wait_for_completion_interruptible() is interrupted by signal, queues aren't setup successfully yet, so we have to fail UBLK_CMD_END_USER_RECOVERY, otherwise kernel oops can be triggered.