Set svn:eol-style for platform-posix.cc to native.

The svn:eol-style property for platform-posix.cc is now set to native. This should get rid of the CR characters in the file added by comitting from Windows and make file lint again.

TBR=erik.corry@gmail.com
Review URL: http://codereview.chromium.org/42639

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1617 ce2b1a6d-e550-0410-aec6-3dcde31c8c00