Allow configuration of profile credentials with the default chain.
Allow configuration of profile credentials with the default chain.

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