Fix S3 integration test expect message.
Fix S3 integration test expect message.

DualSpark/rust-aws,DualSpark/rusoto,rusoto/rusoto,mattico/rusoto,rusoto/rusoto,mattico/rusoto,DualSpark/rusoto,rusoto/rusoto,SecurityInsanity/rusoto,SecurityInsanity/rusoto,DualSpark/rusoto,DualSpark/rust-aws,DualSpark/rust-aws,mattico/rusoto