Switch to golang/dep.

vendor/github.com/cenk/backoff/backoff.go

@@ -15,7 +15,7 @@ import "time"
 // BackOff is a backoff policy for retrying an operation.
 type BackOff interface {
 	// NextBackOff returns the duration to wait before retrying the operation,
-	// or backoff.Stop to indicate that no more retries should be made.
+	// or backoff. Stop to indicate that no more retries should be made.
 	//
 	// Example usage:
 	//