Fix profile provider credential sourcing.
Fix profile provider credential sourcing.

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