Fix OPAL-1753: Unit cannot be selected when importing data in other format than CSV

(cherry picked from commit 4a8d4ae)

Author: Cedric Thiebault

Diff for: opal-gwt-client/src/main/java/org/obiba/opal/web/gwt/app/client/wizard/importdata/presenter/UnitSelectionStepPresenter.java

@@ -14,6 +14,7 @@
 import org.obiba.opal.web.gwt.rest.client.ResourceRequestBuilderFactory;
 import org.obiba.opal.web.model.client.opal.FunctionalUnitDto;
 
+import com.google.common.base.Strings;
 import com.google.gwt.core.client.JsArray;
 import com.google.gwt.event.dom.client.ClickEvent;
 import com.google.gwt.event.dom.client.ClickHandler;
@@ -64,7 +65,7 @@ public void onResource(Response response, JsArray<FunctionalUnitDto> units) {
   }
 
   public void setEntityType(String entityType) {
-    getView().setUnitRadiosEnabled("Participant".equalsIgnoreCase(entityType));
+    getView().setUnitRadiosEnabled(Strings.isNullOrEmpty(entityType) || "Participant".equalsIgnoreCase(entityType));
   }
 
   public void updateImportConfig(ImportConfig importConfig) {