misc/dist: trim space from version string

This prevents us from writing filenames like "weekly.2012-03-12\n.foo.bar.tar.gz".

R=bradfitz
CC=golang-dev
https://golang.org/cl/5783090

misc/dist/bindist.go

@@ -154,6 +154,7 @@ func (b *Build) Do() error {
 	if err != nil {
 		return err
 	}
+	fullVersion = bytes.TrimSpace(fullVersion)
 	v := bytes.SplitN(fullVersion, []byte(" "), 2)
 	version = string(v[0])