[release-branch.go1.3] misc/nacl: remove cmd/link from testzip.proto

There's no cmd/link in this branch.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/102050043

misc/nacl/testzip.proto

diff --git a/misc/nacl/testzip.proto b/misc/nacl/testzip.proto
index 57c2e1b..2701ff4 100644
--- a/misc/nacl/testzip.proto
+++ b/misc/nacl/testzip.proto
@@ -13,9 +13,6 @@
 			gofmt
 				testdata
 					+
-			link
-				testdata
-					+
 		pkg
 			archive
 				tar