Correct error message
Correct error message

This test was previously expecting a different error message than was actually
produced, but the failure was masked by the expection handling in
`SharedIniFileCredentials`. Recent changes made this failure behave differently,
exposing the invalid test.

chrisradek/aws-sdk-js,aws/aws-sdk-js,GlideMe/aws-sdk-js,aws/aws-sdk-js,GlideMe/aws-sdk-js,aws/aws-sdk-js,aws/aws-sdk-js,chrisradek/aws-sdk-js,chrisradek/aws-sdk-js,GlideMe/aws-sdk-js,chrisradek/aws-sdk-js,GlideMe/aws-sdk-js