Enable checkstyle rule for missing defaults in switch statements

Enabled the checkstyle rule that looks for switch statements that
don't have a default label and fixed the violations that were
found.

Code review results for switch statement default branches

Change-Id: I68716894952835def659b4fcab5b381aaf9ff89e
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
index 580e785..869b282 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
@@ -263,6 +263,9 @@
                             reorderedAddedDeviceEvents.remove(id);
                         }
                         break;
+                    default:
+                        log.error("Unknown topology event {}",
+                                  event.eventType());
                 }
             }