ktest: Add POST_INSTALL to allow initrds to be created

Add a POST_INSTALL option that runs after the build and install
but before rebooting to the test kernel. This alls the user to
run a script that will install an initrd (or anything else that may
be special) before booting.

An environment variable KERNEL_VERSION is set.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/tools/testing/ktest/sample.conf b/tools/testing/ktest/sample.conf
index 42f803f..0115a67 100644
--- a/tools/testing/ktest/sample.conf
+++ b/tools/testing/ktest/sample.conf
@@ -93,6 +93,11 @@
 # If you are building a 32bit x86 on a 64 bit host
 #MAKE_CMD = CC=i386-gcc AS=i386-as make ARCH=i386
 
+# If you need an initrd, you can add a script or code here to install
+# it. The environment variable KERNEL_VERSION will be set to the
+# kernel version that is used.
+#POST_INSTALL = ssh user@target /sbin/mkinitrd --allow-missing -f /boot/initramfs-test.img $KERNEL_VERSION
+
 # Way to reboot the box to the test kernel.
 # Only valid options so far are "grub" and "script"
 # (default grub)