build: fix vcbuild merge issues

configure was getting called twice.
We also erroneously introduced support for VS2010,
and were picking 2010 before other versions.

PR-URL: https://github.com/nodejs/io.js/pull/2131


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>