cmd/link: fix addition of -Wl,-z,relro

Not sure how I managed to do this, or get it past review.

Change-Id: I141b97ef8e09dcc9c910c45493a584a3dced2b28
Reviewed-on: https://go-review.googlesource.com/14634Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/link/internal/ld/lib.go

@@ -1001,9 +1001,9 @@ func hostlink() {
 		// anyway.
 		argv = append(argv, "-Wl,-Bsymbolic-functions")
 		if UseRelro() {
-			argv = append(argv, "-shared")
+			argv = append(argv, "-Wl,-z,relro")
 		}
-		argv = append(argv, "-Wl,-z,relro")
+		argv = append(argv, "-shared")
 	}
 
 	if Linkshared && Iself {