Update vendor directory

Re-added cobra patch 499475bb41

vendor/github.com/davecgh/go-spew/spew/bypass.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2015 Dave Collins <dave@davec.name>
+// Copyright (c) 2015-2016 Dave Collins <dave@davec.name>
 //
 // Permission to use, copy, modify, and distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
@@ -13,9 +13,10 @@
 // OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 // NOTE: Due to the following build constraints, this file will only be compiled
-// when the code is not running on Google App Engine and "-tags disableunsafe"
-// is not added to the go build command line.
-// +build !appengine,!disableunsafe
+// when the code is not running on Google App Engine, compiled by GopherJS, and
+// "-tags safe" is not added to the go build command line.  The "disableunsafe"
+// tag is deprecated and thus should not be used.
+// +build !js,!appengine,!safe,!disableunsafe
 
 package spew