fix build issue with clang on mavericks. delete some redundant code

git-svn-id: http://libtorrent.googlecode.com/svn@9988 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
don't use full allocation on network drives (on windows)

git-svn-id: http://libtorrent.googlecode.com/svn@9989 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda