Error handling for KeyValueAction class.

The set --property command requires that the input match
the "key=value" type, but if the type don't match, the return
value will be None, and the command still can be implemented
successfully, this may confuse the users. I think we should
raise exception if the argument type don't match "key=value".
So I make some changes in KeyValueAction class in this patch.

Change-Id: I14e64922faa7e083bc8b5e7e1cac41ef8117c224
Closes-Bug: #1589935

openstackclient/common/parseractions.py

@@ -35,7 +35,9 @@ class KeyValueAction(argparse.Action):
         if '=' in values:
             getattr(namespace, self.dest, {}).update([values.split('=', 1)])
         else:
-            getattr(namespace, self.dest, {}).pop(values, None)
+            msg = _("Expected 'key=value' type, "
+                    "but got: %s") % (str(values))
+            raise argparse.ArgumentTypeError(msg)
 
 
 class MultiKeyValueAction(argparse.Action):

openstackclient/tests/common/test_parseractions.py

@@ -49,16 +49,13 @@ class TestKeyValueAction(utils.TestCase):
         self.assertDictEqual(expect, actual)
 
     def test_error_values(self):
-        results = self.parser.parse_args([
-            '--property', 'red',
-            '--property', 'green=100%',
-            '--property', 'blue',
-        ])
-
-        actual = getattr(results, 'property', {})
-        # There should be no red or blue
-        expect = {'green': '100%', 'format': '#rgb'}
-        self.assertDictEqual(expect, actual)
+        self.assertRaises(
+            argparse.ArgumentTypeError,
+            self.parser.parse_args,
+            [
+                '--property', 'red',
+            ]
+        )
 
 
 class TestMultiKeyValueAction(utils.TestCase):

releasenotes/notes/bug-1589935-8a56e6a18d836db9.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - Raise ``ArgumentTypeError`` if the input arguments do not match the type
+    ``key=value`` when we set properties.
+    [Bug `1589935 <https://bugs.launchpad.net/bugs/1589935>`_]