According to the man page and help info, --debug=integer can specify the
debug_level, while it would report following error:
iscsi-inq --debug=2
iscsi-inq: option '--debug' doesn't allow an argument
It's because the iscsi-inq code did not handle this parameters
correctly. So here we just correct it.
Signed-off-by: Wenchao Hao <haowenchao@huawei.com>