XSDs using atom:link's followed by <any> tags result in ambiguous errors in XSD validators

XSDs using atom:link's followed by <any> tags result in ambiguous errors in XSD validators

Description:
Various Keystone XSD's define atom links followed by <any> attributes which cause XSD tools to report errors ( e.g. Complex Type error X is ambiguous ). This issue exists in a few Keystone XSDs including user.xsd, tenant.xsd & roles.xsd. This may work for the current Python Keystone reference implementation, but other tools and clients wishing to use these XSDs must hand patch these XSDs ( comment out specific atom link lines ) in order to avoid these errors.

Specific Example from user.xsd
.
.
    <complexType name="UserList">
        <sequence>
            <element name="user" type="identity:User" minOccurs="0" maxOccurs="unbounded"/>
            <element vc:minVersion="1.1" ref="atom:link" minOccurs="0" maxOccurs="unbounded" /> <<<<<< PROBLEM
            <any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded" />
        </sequence>
        <anyAttribute namespace="##other" processContents="lax"/>
    </complexType>

XMLSpy reports error as ...
"The content model of complex type definition 'identity:UserList is ambiguous"

Hack / Work Around :

    <complexType name="UserList">
        <sequence>
            <element name="user" type="identity:User" minOccurs="0" maxOccurs="unbounded"/>
            <!-- <element vc:minVersion="1.1" ref="atom:link" minOccurs="0" maxOccurs="unbounded" /> --> <<< COMMENT OUT
            <any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded" />
        </sequence>
        <anyAttribute namespace="##other" processContents="lax"/>
    </complexType>