Better check for integer range to account for 0

We should be using "if value is not None" to better check
for the condition where the value is 0 and 0 is not in the
valid range.

Co-Authored-By: Longjie_Cao <grasson1101@aliyun.com>
Closes-Bug: #1416212
Change-Id: Ie5c81f1916e301619955364b040bdc7a9275e29c

oslo_config/tests/test_types.py

@@ -208,6 +208,7 @@ class IntegerTypeTests(TypeTestHelper, unittest.TestCase):
         t(123)
         t(300)
         t(456)
+        self.assertRaises(ValueError, t, 0)
         self.assertRaises(ValueError, t, 457)
 
 

oslo_config/types.py

@@ -144,7 +144,7 @@ class Integer(ConfigType):
             else:
                 value = int(value)
 
-        if value:
+        if value is not None:
             self._check_range(value)
 
         return value