add Storage Gateway integration tests
add Storage Gateway integration tests

ford-prefect/rusoto,mattico/rusoto,DualSpark/rust-aws,SecurityInsanity/rusoto,DualSpark/rusoto,rusoto/rusoto,rusoto/rusoto,mthjones/rusoto,DualSpark/rust-aws,DualSpark/rusoto,cmsd2/rusoto,noggleboggle/rusoto,indiv0/rusoto,rusoto/rusoto,ford-prefect/rusoto,mattico/rusoto,mattico/rusoto,DualSpark/rusoto,mthjones/rusoto,DualSpark/rust-aws,SecurityInsanity/rusoto