‘misc_items’ may be used uninitialized in stlink_usb.c/stlink_dap_op_queue_run_interna

[domologic]

I've already created a pull request about this issue (https://github.com/STMicroelectronics/OpenOCD/pull/13) which has been closed automatically because I need to sign a contributors agreement. Because this doesn't justify the effort for me, I've created this issue.