win: bring back xp/2k3 support

Issue: https://github.com/joyent/node/issues/25348
The gyp/project files don't explicitly specify a subsystem version,
which results in the default being used. The default changed from
VS 2010 to VS 2012 and later.

Backport e8d08503 from io.js.
Original commit message follows:

Chrome still runs on Windows XP, so there is no reason that iojs
couldn't.

PR: https://github.com/iojs/io.js/pull/512
(cherry picked from commit e8d08503

)

Reviewed-By: Julien Gilli <julien.gilli@joyent.com>
PR-URL: https://github.com/joyent/node/pull/25367