tcmu/qcow: Fix qcow to work with read/writes
tcmu/qcow: Fix qcow to work with read/writes

Signed-off-by: Bryant G. Ly <1024ba5f11bcf6a7ffb2ce4b8b54f508dfeeefbd@linux.vnet.ibm.com>

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