[FIX] vault client: fixed incorrect username normalization
[FIX] vault client: fixed incorrect username normalization

darkdarkdragon/ripple-lib,ripple/ripple-lib,ripple/ripple-lib,wilsonianb/ripple-lib,darkdarkdragon/ripple-lib,wilsonianb/ripple-lib,darkdarkdragon/ripple-lib,ripple/ripple-lib,wilsonianb/ripple-lib,ripple/ripple-lib