Cleaned up warnings reported by the Javadoc tool.

Javadoc reports warnings for things such as missing return descriptions,
missing or wrong parameters, invalid tags.

Note: I didn't touch any of the warnings in the OpenflowJ code.

Change-Id: I7234f617e092b489fad599196fc9cbe78f7e2db1
diff --git a/src/main/java/net/onrc/onos/apps/sdnip/IPatriciaTree.java b/src/main/java/net/onrc/onos/apps/sdnip/IPatriciaTree.java
index fa548b2..21cb823 100644
--- a/src/main/java/net/onrc/onos/apps/sdnip/IPatriciaTree.java
+++ b/src/main/java/net/onrc/onos/apps/sdnip/IPatriciaTree.java
@@ -78,7 +78,7 @@
 
     /**
      * Represents an entry in the patricia tree. The {@code Entry} is a mapping
-     * from {@link Prefix} to a {@link V} value object.
+     * from {@link Prefix} to a value object of type {@code V}.
      *
      * @param <V> the class of objects stored in the tree
      */