Merge two attributes in Shibboleth v3

[Peter Schober]

* Peter Schober <peter.schober at univie.ac.at> [2018-03-17 15:46]:
> Of course you were providing the literal answer to the question in the
> subject. That is slightly weird in v3, though mostly because of the
> resulting when having differing attribute names from different
> dependencies, which can be silenced via logback.

Sigh. That should have been "the resulting *warning* ..."
which you could get rid of with this:

<logger name="net.shibboleth.idp.attribute.resolver.PluginDependencySupport" level="ERROR"/>

None of this applies to the OP because there is only one attribute in
that use-case, not two. (Just to avoid further confusion.)
-peter