ironic-agent: ensure dmidecode and ipmitool are installed

Currently they are used for inspection, but may be also used for
other purposes, as they're accessed from IPA generic hardware layer.

Change-Id: I32c6a711d466131b9445023812a2a260ed2e01f3

elements/ironic-agent/package-installs.yaml

@@ -1,2 +1,5 @@
 tgt:
 curl:
+# this one requires workaround with dnf - see 80-ironic-agent for details
+dmidecode:
+ipmitool:

elements/ironic-agent/post-install.d/80-ironic-agent

@@ -7,6 +7,12 @@ set -eu
 set -o pipefail
 
 install-packages -e python-dev git cloud-init
+# dnf removes unused dependencies by default. As we installed cloud-init before
+# dmidecode, dnf removes dmidecode above as an unused dependency.
+# TODO(dtantsur): use `dnf mark` from dnf 1.1.1 in install-packages once this
+# command is widely available.
+install-packages dmidecode
+
 rm -rf /tmp/ironic-python-agent
 
 case "$DIB_INIT_SYSTEM" in