Switch to exit_on_error mode

Switch several programs to newer exit_on_error mode.  This mode dictates
the behavior of the validation functions.

Also, valid_value recently:
- Switched the order of 2 positional arguments
- Added code to default invalid_values to ["", None] vs [""]

Changed Auto_reboot/cp_master accordingliny.

Change-Id: I3ade00d8b51d567604f59ff6c8f993f4afc864ee
Signed-off-by: Michael Walsh <micwalsh@us.ibm.com>
diff --git a/bin/plug_ins/Stop/cp_stop_check b/bin/plug_ins/Stop/cp_stop_check
index acaddfe..713bd96 100755
--- a/bin/plug_ins/Stop/cp_stop_check
+++ b/bin/plug_ins/Stop/cp_stop_check
@@ -21,6 +21,9 @@
 # Restore sys.path[0].
 sys.path.insert(0, save_path_0)
 
+# Set exit_on_error for gen_valid functions.
+set_exit_on_error(True)
+
 # Initialize.
 STOP_REST_FAIL = ''
 STOP_COMMAND = ''
@@ -95,8 +98,7 @@
 
     get_plug_vars()
 
-    if not valid_value(AUTOBOOT_OPENBMC_HOST, ["", None]):
-        return False
+    valid_value(AUTOBOOT_OPENBMC_HOST)
 
     gen_post_validation(exit_function, signal_handler)