Javadoc fixes.

Change-Id: Ic2cef19a6f1af9916c8615c9319cc122d9da5383
diff --git a/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/FlowModBuilder.java b/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/FlowModBuilder.java
index 793c9f3..c488192 100644
--- a/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/FlowModBuilder.java
+++ b/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/FlowModBuilder.java
@@ -72,6 +72,7 @@
      *
      * @param flowRule the flow rule to transform into a flow mod
      * @param factory the OpenFlow factory to use to build the flow mod
+     * @param xid the transaction ID
      * @return the new flow mod builder
      */
     public static FlowModBuilder builder(FlowRule flowRule,
@@ -92,6 +93,7 @@
      *
      * @param flowRule the flow rule to transform into a flow mod
      * @param factory the OpenFlow factory to use to build the flow mod
+     * @param xid the transaction ID
      */
     protected FlowModBuilder(FlowRule flowRule, OFFactory factory, Optional<Long> xid) {
         this.factory = factory;