aws-xray-recorder-sdk-sql has incorrect implementations for isWrapperFor

[chamsco-aws]

In the merge #104 we added the TracingDataSource and the TracingConnection classes. In those classes the implementation of isWrapperFor and unwrap is flawed

https://github.com/aws/aws-xray-sdk-java/blob/master/aws-xray-recorder-sdk-sql/src/main/java/com/amazonaws/xray/sql/TracingConnection.java#L309-L317

https://github.com/aws/aws-xray-sdk-java/blob/master/aws-xray-recorder-sdk-sql/src/main/java/com/amazonaws/xray/sql/TracingDataSource.java#L48-L56

Right now you can not test using those methods if the tracing connection or datasource was applied. The correct implementation would be

    @Override
    @SuppressWarnings("unchecked")
    public <T> T unwrap(Class<T> iface) throws SQLException {
        if (iface.isInstance(this)) {
            return (T) this;
        }
        return delegate.unwrap(iface);
    }

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        return (iface.isInstance(this) || delegate.isWrapperFor(iface);
    }