Merge "Avoid to install a blank list of packages"

elements/yum/bin/install-packages

@@ -80,7 +80,10 @@ if [ -n "$WHITELIST" ]; then
     else
         PKGS=$(map-packages $WHITELIST)
     fi
-    echo "Installing $PKGS"
+    if [ -z "${PKGS}" ]; then
+        echo "Not running install-packages $ACTION with empty packages list"
+    else
+        echo "Running install-packages ${ACTION}. Package list: $PKGS"
         yum -y $ACTION $EXTRA_ARGS $PKGS
         for pkg in "$@"; do
             if [ "$pkg" = "python-pip" ] ; then
@@ -88,3 +91,4 @@ if [ -n "$WHITELIST" ]; then
             fi
         done
     fi
+fi