Merge remote-tracking branch 'remotes/origin/dev' into soup-verify-salt

salt/common/tools/sbin/so-image-common

@@ -105,7 +105,11 @@ update_docker_containers() {
   fi
 
   if [ -z "$LOG_FILE" ]; then
+    if [ -c /dev/tty ]; then
       LOG_FILE=/dev/tty
+    else
+      LOG_FILE=/dev/null
+    fi
   fi
 
   # Recheck the version for scenarios were the VERSION wasn't known before this script was imported