Renamed Trie to Tree for consistency.

This is in the context of SDN-IP's patricia tree.

Change-Id: I59437fb49580aba01a287e9bc0bf035c093c7b95
diff --git a/src/main/java/net/onrc/onos/apps/bgproute/RibEntry.java b/src/main/java/net/onrc/onos/apps/bgproute/RibEntry.java
index 7ad1d3d..2392e01 100644
--- a/src/main/java/net/onrc/onos/apps/bgproute/RibEntry.java
+++ b/src/main/java/net/onrc/onos/apps/bgproute/RibEntry.java
@@ -19,8 +19,8 @@
     /*
      * Store the sequence number information provided on the update here for
      * now. I think this *should* really be in the RibUpdate, and we should
-     * store RibUpdates in the Ptrie. But, that's a bigger change to change
-     * what the Ptrie stores.
+     * store RibUpdates in the Ptree. But, that's a bigger change to change
+     * what the Ptree stores.
      */
     private final long sysUpTime;
     private final long sequenceNum;