Cleaned up a slew of Javadoc errors in preparation for switch over to Java 8.
diff --git a/core/api/src/main/java/org/onlab/onos/net/provider/ProviderRegistry.java b/core/api/src/main/java/org/onlab/onos/net/provider/ProviderRegistry.java
index a2497f0..8cab8a8 100644
--- a/core/api/src/main/java/org/onlab/onos/net/provider/ProviderRegistry.java
+++ b/core/api/src/main/java/org/onlab/onos/net/provider/ProviderRegistry.java
@@ -38,9 +38,10 @@
* Unregisters the supplied provider. As a result the previously issued
* provider service will be invalidated and any subsequent invocations
* of its methods may throw {@link java.lang.IllegalStateException}.
- * <p/>
+ * <p>
* Unregistering a provider that has not been previously registered results
* in a no-op.
+ * </p>
*
* @param provider provider to be unregistered
*/