libgo: ^M in source files

[Mike Stump]

So I found some ^Ms in libgo.

$ grep -l '^M' libgo/go/mime/multipart/testdata/nested-mime
libgo/go/mime/multipart/testdata/nested-mime

This file is likely meant to contain them if I don't miss my guess.  The problem is, it is not tagged as a binary file in svn and git, leading to inconsistent contents depending upon how it is pulled.  Could you either tag as binary in svn/git or strip the the ^Ms, thanks.