libgo patch committed: Remove empty directories

[Ian Lance Taylor]

The svn cp I used to copy libgo into trunk created several empty
directories, which used to hold files on the branch but no longer do.  I
deleted the files on the branch but not the directories.  I committed a
patch to delete the following empty directories in libgo:

go/nntp
go/bignum
go/exp/bignum
go/exp/iterable
go/exp/parser
go/exp/exception
go/xgb
go/once
go/malloc

There is no associated diff as there were no files in those directories.

Ian