Make sure dnf won't autoremove packages that we explicitly installed

As dnf 1.1.1 is pretty recent, make sure we update it as early as possible.

Change-Id: I30039090cfe652b864d847713ab2986c5659023d

elements/yum/bin/install-packages

@@ -124,6 +124,13 @@ if [ -n "$WHITELIST" ]; then
 
     ${YUM} -v -y $ACTION $EXTRA_ARGS $PKGS
 
+    if [ "$ACTION" == "install" ]; then
+        if [ ${YUM} == "dnf" ]; then
+            # Make sure dnf won't autoremove these packages
+            dnf mark install $PKGS
+        fi
+    fi
+
     # probably not the right place for this; but python-pip package on
     # fedora/rh calls pip "pip-python" while the rest of the work
     # expects it to be just called "pip"

elements/yum/pre-install.d/00-dnf-update

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+if [[ $DISTRO_NAME == "fedora" && $DIB_RELEASE -eq 22 ]]; then
+    # we need dnf mark command from dnf 1.1.1, which is pretty recent
+    dnf --refresh update -y dnf
+fi