Add __ne__ built-in function

In Python 3 __ne__ by default delegates to __eq__ and inverts the
result, but in Python 2 they urge you to define __ne__ when you
define __eq__ for it to work properly [1].There are no implied
relationships among the comparison operators. The truth of x==y
does not imply that x!=y is false. Accordingly, when defining
__eq__(), one should also define __ne__() so that the operators
will behave as expected.
[1]https://docs.python.org/2/reference/datamodel.html#object.__ne__

Change-Id: I40878c38fd27933d73225ba49bd69b425f13dc6a

cinder/objects/base.py

@@ -428,6 +428,9 @@ class CinderComparableObject(base.ComparableVersionedObject):
             return self.obj_to_primitive() == obj.obj_to_primitive()
         return False
 
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
 
 class ObjectListBase(base.ObjectListBase):
     def obj_make_compatible(self, primitive, target_version):

cinder/tests/unit/test_hpe3par.py

@@ -87,6 +87,9 @@ class Comment(object):
     def __eq__(self, actual):
         return (dict(ast.literal_eval(actual)) == self.expected)
 
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
 
 class HPE3PARBaseDriver(object):
 

cinder/volume/drivers/netapp/dataontap/client/api.py

@@ -403,6 +403,9 @@ class NaElement(object):
     def __eq__(self, other):
         return str(self) == str(other)
 
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
     def __hash__(self):
         return hash(str(self))