manager_test:add err check for ioutil.TempDir
manager_test:add err check for ioutil.TempDir

Signed-off-by: Zhou Hao <f577ade201aa03d612c19915a089dc6084d45cd9@fujitsu.com>

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