chg rcp facet copiefield to list

solr/gfl/conf/schema.xml

@@ -139,7 +139,7 @@
   <!-- Solr needs string fields to sort correctly -->
   <field name="author_sort" type="string" multiValued="true"/>
   <copyField source="author" dest="author_sort" />
-  <field name="recipient_sort" type="string" />
+  <field name="recipient_sort" type="string"  multiValued="true"  />
   <copyField source="recipient" dest="recipient_sort" />
   <field name="origin_place_sort" type="string" />
   <copyField source="origin_place" dest="origin_place_sort" />