Fix issue tests 1.1.9 and 1.1.10 (#911)

Issue https://github.com/aquasecurity/kube-bench/issues/909

cfg/cis-1.6/master.yaml

@@ -121,7 +121,7 @@ groups:
       - id: 1.1.9
         text: "Ensure that the Container Network Interface file permissions are set to 644 or more restrictive (Manual)"
         audit: |
-          ps -ef | grep $kubeletbin | grep -- --cni-conf-dir | sed 's%.*cni-conf-dir[= ]\([^ ]*\).*%\1%' | xargs -I{} find {} -mindepth 1 | xargs stat -c permissions=%a
+          ps -ef | grep $kubeletbin | grep -- --cni-conf-dir | sed 's%.*cni-conf-dir[= ]\([^ ]*\).*%\1%' | xargs -I{} find {} -mindepth 1 | xargs --no-run-if-empty stat -c permissions=%a
           find /var/lib/cni/networks -type f 2> /dev/null | xargs --no-run-if-empty stat -c permissions=%a
         use_multiple_values: true
         tests:
@@ -139,7 +139,7 @@ groups:
       - id: 1.1.10
         text: "Ensure that the Container Network Interface file ownership is set to root:root (Manual)"
         audit: |
-          ps -ef | grep $kubeletbin | grep -- --cni-conf-dir | sed 's%.*cni-conf-dir[= ]\([^ ]*\).*%\1%' | xargs -I{} find {} -mindepth 1 | xargs stat -c %U:%G
+          ps -ef | grep $kubeletbin | grep -- --cni-conf-dir | sed 's%.*cni-conf-dir[= ]\([^ ]*\).*%\1%' | xargs -I{} find {} -mindepth 1 | xargs --no-run-if-empty stat -c %U:%G
           find /var/lib/cni/networks -type f 2> /dev/null | xargs --no-run-if-empty stat -c %U:%G
         use_multiple_values: true
         tests: