ktest: Still do reboot even for REBOOT_TYPE = script

The REBOOT_TYPE may be either grub or script, if it is script
it is expected that a REBOOT_SCRIPT is defined.

With the SWITCH_TO_TEST which is the complement of SWITCH_TO_GOOD,
which does basically the same thing as REBOOT_SCRIPT and but for
both grub and script, the REBOOT_SCRIPT does not need to be mandatory
anymore.

Do not require the REBOOT_SCRIPT and always run the reboot code
for both grub and script.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

tools/testing/ktest/sample.conf

@@ -346,7 +346,10 @@
 #GRUB_MENU = Test Kernel
 
 # A script to reboot the target into the test kernel
-# (Only mandatory if REBOOT_TYPE = script)
+# This and SWITCH_TO_TEST are about the same, except
+# SWITCH_TO_TEST is run even for REBOOT_TYPE = grub.
+# This may be left undefined.
+# (default undefined)
 #REBOOT_SCRIPT =
 
 #### Optional Config Options (all have defaults) ####