boto/botocore — pull request #369 by jamesls (2014-10-31 23:44:17+00:00)
Title: Don't use credential provider if credentials are given

If the `aws_*` params are provided in a `create_client()` call,
we still call `session.get_credentials()`, which is an unnecessary
call. We should only invoke the credential lookup process if
explicit credentials are not provided in the call to
`create_client()`.

cc @kyleknap @danielgtaylor