meta/bandwidth: package main so we can build a binary

plugins/meta/bandwidth/ifb_creator.go

@@ -1,5 +1,3 @@
-package bandwidth
-
 // Copyright 2018 CNI authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,6 +12,8 @@ package bandwidth
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+package main
+
 import (
 	"fmt"
 	"net"