[release-branch.go1.4] remove cmd/link from nacl test zip

LGTM=dsymonds
R=rsc, dsymonds
CC=golang-codereviews
https://golang.org/cl/179830043

misc/nacl/testzip.proto

diff --git a/misc/nacl/testzip.proto b/misc/nacl/testzip.proto
index fd0c6a0..07d4a1d 100644
--- a/misc/nacl/testzip.proto
+++ b/misc/nacl/testzip.proto
@@ -18,9 +18,6 @@
 				gofmt_test.go
 				testdata
 					+
-			link
-				testdata
-					+
 		archive
 			tar
 				testdata