Reduce severity of generic discrete assert to 'Ok'

In practice, generic discrete sensors have not indicated good *or* bad
health They have most commonly been used to indicate something like a
particular option being available or user disabled.  This does mean
that something trying to use an utterly generic discrete sensor will
not trigger a health issue, but hopefully those cases leverage more
informative events that do have clear 'health' connotations.  There
remains the chance that a sensor will rely upon the vocabulary of
the text in SDR and that just cannot be avoided.

Change-Id: I777b2f1300301291ca5a3aa7a6b18de1de6f9d1a

pyghmi/ipmi/private/constants.py

@@ -80,9 +80,9 @@ sensor_type_codes = {
 }
 
 # This is from table 42-2
-#For severity, we really have very little to go on in this case
-#Optimistically assume 'warning' when generic sensors have something
-#to assert
+#digital discrete poses a challenge from a health perspective.  So far all
+#observed ones are no more or less 'healthy' by being asserted or not asserted
+#for example asserting that an add-on is installed
 
 discrete_type_offsets = {
     2: {
@@ -106,7 +106,7 @@ discrete_type_offsets = {
         },
         1: {
             'desc': 'Asserted',
-            'severity': const.Health.Warning,
+            'severity': const.Health.Ok,
         },
     },
     4: {