Need to revert the usage of streams, as EclipseLink 2.5 is broken.

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=429992

As we are stuck on Glassfish 4.1 for now (see IQSS#4172, IQSS#4248 and IQSS#4260),
we cannot simply upgrade. Meh.

This reverts commit c80aeea.

src/main/java/edu/harvard/iq/dataverse/DatasetField.java

@@ -11,7 +11,6 @@
  */
 import java.io.Serializable;
 import java.util.*;
-import java.util.stream.Collectors;
 import javax.persistence.CascadeType;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
@@ -209,11 +208,13 @@ public void setControlledVocabularyValues(List<ControlledVocabularyValue> contro
      * @return List of matching vocabulary items (containing the query string in their l18n string)
      */
     public Collection<ControlledVocabularyValue> completeVocabulary(String query) {
-        String q = query.toLowerCase();
-        return this.getDatasetFieldType().getControlledVocabularyValues()
-                .stream()
-                .filter(cvv -> cvv.getLocaleStrValue().toLowerCase().contains(q))
-                .collect(Collectors.toList());
+        Collection<ControlledVocabularyValue> filtered = new ArrayList<>();
+        for (ControlledVocabularyValue item : this.getDatasetFieldType().getControlledVocabularyValues()) {
+            if (item.getLocaleStrValue().toLowerCase().contains(query.toLowerCase())) {
+                filtered.add(item);
+            }
+        }
+        return filtered;
     }
 
     /**