Fix creating target paths in file_util_posix CopyDirectory.

BUG=167840


Review URL: https://chromiumcodereview.appspot.com/11773018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176659 0039d316-1c4b-4281-b951-d872f2087c98
bool SetCurrentDirectory(const FilePath& path) {
  base::ThreadRestrictions::AssertIOAllowed();
  int ret = chdir(path.value().c_str());
  return !ret;
}

bool SetCurrentDirectory(const FilePath& path) {
  base::ThreadRestrictions::AssertIOAllowed();
  int ret = chdir(path.value().c_str());
  return !ret;
}
