A request path with an invalid percent escape, such as "/bucket/%zz",
failed url.PathUnescape in the DecodeURL middleware and the raw error
was answered with 500 InternalError. S3 rejects such a request with
400 InvalidURI.
Return InvalidURI from DecodeURL, so the s3 and admin routers answer
with it as well, and let the website handler pass the error through
instead of mapping it on its own.
Fixes#2070
A region specific endpoint requires CreateBucket to name that same region
in `LocationConstraint`. The gateway reported a mismatch as
`InvalidLocationConstraint`, which AWS reserves for a constraint that is
not a valid location at all, and accepted a request that omitted the
constraint entirely.
Keep `InvalidLocationConstraint` for the global `us-east-1` endpoint,
which takes no constraint, and return
`IllegalLocationConstraintException` when a region specific endpoint gets
a constraint naming another region, or none.
Fixes#2246