[Metadata] Add IDPSSODescriptor.Extensions.Scope

[peppelinux]

http://shibboleth.net/pipermail/users/2013-July/010958.html

Otherwise Shibboleth SP AttrChecker will apply this rule in /etc/shibboleth/attribute-policy.xml

    Shared rule for all "scoped" attributes, but you'll have to manually apply it inside
    an AttributeRule for each attribute you want to check.
    <afp:PermitValueRule id="ScopingRules" xsi:type="AND">
        <Rule xsi:type="NOT">
            <Rule xsi:type="AttributeValueRegex" regex="@"/>
        </Rule>
        <Rule xsi:type="saml:AttributeScopeMatchesShibMDScope"/>
    </afp:PermitValueRule>

Comment it as a workaround or disable AttrChecker (not recommended)

[peppelinux]

Here:
ce3a86a

otherwise here an example with shibmd extension
https://github.com/IdentityPython/pysaml2/blob/c1fab71cf9f24dce4cc8985061c45a19481dcec0/tests/sp_mdext_conf.py#L48