win32.c: fail before getting ITEMIDLIST
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55269 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
win32.c: fail before getting ITEMIDLIST
ITEMIDLIST if the buffer is less than 260 word which
SHGetPathFromIDListW requires.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55269 b2dd03c8-39d4-4d8f-98ff-823fe69b080e