Fix use of botocore Config object

Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>

app/s3_client/__init__.py

@@ -25,10 +25,9 @@ def get_s3_object(
     session = Session(
         aws_access_key_id=access_key,
         aws_secret_access_key=secret_key,
-        region_name=region,
-        config=AWS_CLIENT_CONFIG
+        region_name=region
     )
-    s3 = session.resource('s3')
+    s3 = session.resource('s3', config=AWS_CLIENT_CONFIG)
     obj = s3.Object(bucket_name, filename)
     return obj