make property deletions evaluate to false for convenience

test/property/test_property_deletion.py

@@ -0,0 +1,8 @@
+from unittest import TestCase
+from owrx.property import PropertyDeletion
+
+
+class PropertyDeletionTest(TestCase):
+    def testDeletionEvaluatesToFalse(self):
+        deletion = PropertyDeletion()
+        self.assertFalse(deletion)