Remove direct i/o requirement for some unit tests
Remove direct i/o requirement for some unit tests

Some disk cace settings require direct i/o support on the disk location.
Some unit tests set these settings, without actually testing direct i/o
logic. Changing them to not require  direct i/o to test their actual
logic.

Signed-off-by: Roman Mohr <6da0130c5aeef94e5bbaabadbf8017270be25c64@redhat.com>

davidvossel/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt