qcow: initialize coroutine mutex commit 52b8eb60132b27ad53476490e9d7579003390cfa added a mutex, but never initialized it. This caused a segfault. Reported-by: Alexander Graf <agraf@suse.de> Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>