Always use element namespace as target namespace

[veewee]

Q	A
Type	bug
BC Break	no
Fixed issues	phpro/soap-client#585

Summary

Fixes phpro/soap-client#585

<xs:schema xmlns="http://www.capita-software-services.com/scp/simple"
           xmlns:scpbase="http://www.capita-software-services.com/scp/base"
           xmlns:xs="http://www.w3.org/2001/XMLSchema" attributeFormDefault="unqualified"
           elementFormDefault="qualified" targetNamespace="http://www.capita-software-services.com/scp/simple">
    <xs:import namespace="http://www.capita-software-services.com/scp/base"/>
    <xs:element name="scpSimpleQueryRequest" type="scpbase:scpQueryRequest"/>
<xs:schema>

Previously, this resulted in the element scpSimpleQueryRequest being targeted to the scpbase namespace.
This is not correct, given that the element is axtyally in the simple namespace, which results in the type collection not being able to find this element. (only the complexType in scpbase).

This fixes that issue and makes sure the element is also encoded as scpSimple in the encoder.