Remove /var/tmp/* from images

In some cases, things such as dracut regenerating the
initramfs file, may leave some artifacts in /var/tmp/ from
the ramdisk build. These are not needed and can be discarded.

Change-Id: Ibd2a61a7e42adfea868679c52c7a786d9aab1b36

dib/ironic-python-agent-ramdisk/post-install.d/99-remove-extra-packages

@@ -34,3 +34,7 @@ case "$DISTRO_NAME" in
         rpm --rebuilddb
         ;;
 esac
+
+# NOTE(TheJulia): remove any excess temporary files from /var/tmp
+# In particular, dracut may leave some items we don't need/want.
+rm -r -f /var/tmp/*

releasenotes/notes/clean-var-tmp-with-dib-builds-cd31a2cf70a7f935.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixes excess files being housed in /var/tmp inside of a ramdisk image
+    which may, in some cases, result in a much larger ramdisk than expected.
+    Files and folders in /var/tmp within a ramdisk are now removed prior to
+    the ramdisk being packaged as part of a DIB based image build.