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

The revert of this caused CI failures for Ironic in the
Ironic-Python-Agent builds.

This reverts commit 4f2613d815.

Change-Id: I0963d3decefb62680f720bdc3dddd19ecb3bdfd4

diskimage_builder/elements/yum/bin/install-packages

@@ -135,6 +135,13 @@ if [ -n "$WHITELIST" ]; then
     # [1] https://bugzilla.redhat.com/show_bug.cgi?id=965567
     set -o xtrace
     ${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
     $_xtrace
 
     # probably not the right place for this; but python-pip package on

diskimage_builder/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