win,msi: warn that older io.js needs manual uninstall
win,msi: warn that older io.js needs manual uninstall

Because the UpgradeCode changes with version 1.0.2, older versions won't
be uninstalled automatically. This patch puts a warning in the
installer.

PR: https://github.com/iojs/io.js/pull/431
Reviewed-by: Rod Vagg <f9f03903429036ef609ed7ca822fddfa76155c29@vagg.org>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node