also look for VStudio installation in: HKLM\Software\WOW6432Node\Microsoft\VisualStudio\SxS\VC7

Change-Id: I4f01a8f73504b5482e38fe4cef1b2a1bb0ada2bd
Reviewed-on: http://review.couchbase.org/29219
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>