Adding and fixing javados.

Change-Id: I38eddb0b11630cdd83c5d1e5d5dc393ee2555897
diff --git a/providers/null/flow/src/main/java/org/onosproject/provider/nil/flow/impl/package-info.java b/providers/null/flow/src/main/java/org/onosproject/provider/nil/flow/impl/package-info.java
index cd26203..8ebd2c4 100644
--- a/providers/null/flow/src/main/java/org/onosproject/provider/nil/flow/impl/package-info.java
+++ b/providers/null/flow/src/main/java/org/onosproject/provider/nil/flow/impl/package-info.java
@@ -15,6 +15,6 @@
  */
 
 /**
- * Null provider that will accept any flow.
+ * Provider that will accept any flow rules.
  */
 package org.onosproject.provider.nil.flow.impl;