AWSRetry: allow retrying on additional ClientError exceptions (#28483)

* Added the ability to extend the exception list in CloudRetry

* AWSRetry boto and boto compatible

* Updated tests to reflect boto/boto3

* Added boto to shippable requirements

* Have base_class and added_exceptions default to None in CloudRetry

AWSRetry - only retry on boto3 exceptions and remove boto requirement from tests

* Make requested changes.

test/units/module_utils/ec2/test_aws.py

@@ -44,6 +44,22 @@ class RetryTestCase(unittest.TestCase):
         r = no_failures()
         self.assertEqual(self.counter, 1)
 
+    def test_extend_boto3_failures(self):
+        self.counter = 0
+        err_msg = {'Error': {'Code': 'MalformedPolicyDocument'}}
+
+        @AWSRetry.backoff(tries=2, delay=0.1, catch_extra_error_codes=['MalformedPolicyDocument'])
+        def extend_failures():
+            self.counter += 1
+            if self.counter < 2:
+                raise botocore.exceptions.ClientError(err_msg, 'Could not find you')
+            else:
+                return 'success'
+
+        r = extend_failures()
+        self.assertEqual(r, 'success')
+        self.assertEqual(self.counter, 2)
+
     def test_retry_once(self):
         self.counter = 0
         err_msg = {'Error': {'Code': 'InstanceId.NotFound'}}