rds: do not update multi-az unless specified - fixes #23385 (#23498)

* allow multi_az to be unmodified if not explicitly specified

* fix pep8 and remove from legacy files

lib/ansible/modules/cloud/amazon/rds.py

@@ -349,6 +349,7 @@ DEFAULT_PORTS= {
     'postgres': 5432,
 }
 
+
 class RDSException(Exception):
     def __init__(self, exc):
         if hasattr(exc, 'error_message') and exc.error_message:
@@ -481,8 +482,8 @@ class RDS2Connection:
     def create_db_instance(self, instance_name, size, instance_class, db_engine,
                            username, password, **params):
         try:
-            result = self.connection.create_db_instance(instance_name, size, instance_class,
+            result = self.connection.create_db_instance(instance_name, size, instance_class, db_engine, username, password,
-                db_engine, username, password, **params)['CreateDBInstanceResponse']['CreateDBInstanceResult']['DBInstance']
+                                                        **params)['CreateDBInstanceResponse']['CreateDBInstanceResult']['DBInstance']
             return RDS2DBInstance(result)
         except boto.exception.BotoServerError as e:
             raise RDSException(e)
@@ -594,8 +595,6 @@ class RDSDBInstance:
         return d
 
 
-
-
 class RDS2DBInstance:
     def __init__(self, dbinstance):
         self.instance = dbinstance
@@ -1081,7 +1080,7 @@ def main():
         engine_version=dict(required=False),
         parameter_group=dict(required=False),
         license_model=dict(choices=['license-included', 'bring-your-own-license', 'general-public-license', 'postgresql-license'], required=False),
-        multi_zone        = dict(type='bool', default=False),
+        multi_zone=dict(type='bool', required=False),
         iops=dict(required=False),
         security_groups=dict(required=False),
         vpc_security_groups=dict(type='list', required=False),

test/sanity/pep8/legacy-files.txt

@@ -198,7 +198,6 @@ lib/ansible/modules/cloud/amazon/iam_policy.py
 lib/ansible/modules/cloud/amazon/iam_server_certificate_facts.py
 lib/ansible/modules/cloud/amazon/lambda.py
 lib/ansible/modules/cloud/amazon/lambda_facts.py
-lib/ansible/modules/cloud/amazon/rds.py
 lib/ansible/modules/cloud/amazon/rds_param_group.py
 lib/ansible/modules/cloud/amazon/rds_subnet_group.py
 lib/ansible/modules/cloud/amazon/redshift.py