misc/dist: fix file regexp

This step makes it possible to upload the -osx10.x binaries
separately to their construction (after signing, for example).

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/28160043

misc/dist/bindist.go

@@ -117,8 +117,7 @@ var staticLinkAvailable = []string{
 	"netbsd",
 }
 
-var fileRe = regexp.MustCompile(
-	`^(go[a-z0-9-.]+)\.(src|([a-z0-9]+)-([a-z0-9]+)(?:-([a-z0-9.]))?)\.`)
+var fileRe = regexp.MustCompile(`^(go[a-z0-9-.]+)\.(src|([a-z0-9]+)-([a-z0-9]+)(?:-([a-z0-9.]+))?)\.(tar\.gz|zip|pkg|msi)$`)
 
 func main() {
 	flag.Usage = func() {