Disable log flush on docker container

Signed-off-by: Christian König <github@yubiuser.dev>

pihole

@@ -92,8 +92,12 @@ debugFunc() {
 }
 
 flushFunc() {
+    if [ -n "${DOCKER_VERSION}" ]; then
+        unsupportedFunc
+    else
         "${PI_HOLE_SCRIPT_DIR}"/piholeLogFlush.sh "$@"
         exit 0
+    fi
 }
 
 # Deprecated function, should be removed in the future