Use RepositoryEvent.newDiscoveryEvent(..) and pass the nickname

Currently even if a reference would define a nickname it is not passed
by the repository event resulting in an updatesite to have an empty
name.

This uses the RepositoryEvent.newDiscoveryEvent(...) method to pass the
nickname is present.

bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/LocalMetadataRepository.java

@@ -186,13 +186,14 @@ public void initialize(RepositoryState state) {
 	 */
 	public void publishRepositoryReferences() {
 		IProvisioningEventBus bus = getProvisioningAgent().getService(IProvisioningEventBus.class);
-		if (bus == null)
+		if (bus == null) {
 			return;
-
+		}
 		List<IRepositoryReference> repositoriesSnapshot = createRepositoriesSnapshot();
 		for (IRepositoryReference reference : repositoriesSnapshot) {
-			bus.publishEvent(new RepositoryEvent(reference.getLocation(), reference.getType(),
-					RepositoryEvent.DISCOVERED, reference.isEnabled()));
+			RepositoryEvent event = RepositoryEvent.newDiscoveryEvent(reference.getLocation(), reference.getNickname(),
+					reference.getType(), reference.isEnabled());
+			bus.publishEvent(event);
 		}
 	}