[VOL-1588] Improve Flow Add performance

This update consists of the following:
1) Update the performance when adding a flow to a logical device,
decomposing the flow into parent and child device and sending the
flow to the adapters.
2) Format a number of files as per GO fmt.
3) Ensure the device graph cache gets updated when a new port is
added to the graph that belongs to an existing device in cache.

The flow update/deletion performance will be addressed in a separate
commit.

Change-Id: I2eb663cc73eef9fc6172203ed88a35726f5fe008
diff --git a/kafka/client.go b/kafka/client.go
index a4c49ca..3d37f6e 100644
--- a/kafka/client.go
+++ b/kafka/client.go
@@ -32,7 +32,7 @@
 
 const (
 	GroupIdKey = "groupId"
-	Offset = "offset"
+	Offset     = "offset"
 )
 
 const (