cri: set default masked/readonly paths to empty paths

Fixes #5029.

Signed-off-by: Yohei Ueda <yohei@jp.ibm.com>

pkg/cri/server/container_create_linux_test.go

@@ -1118,8 +1118,8 @@ func TestMaskedAndReadonlyPaths(t *testing.T) {
 			disableProcMount: false,
 			masked:           nil,
 			readonly:         nil,
-			expectedMasked:   defaultSpec.Linux.MaskedPaths,
-			expectedReadonly: defaultSpec.Linux.ReadonlyPaths,
+			expectedMasked:   []string{},
+			expectedReadonly: []string{},
 			privileged:       false,
 		},
 		"should be able to specify empty paths": {