Installer: Cannot proceed from IIS Configuration Settings screen on Windows 10

[jng]

The issue is that the launch condition for the next dialog is

MGWEB_CONFIG="IIS" AND IISVERSIONMAJOR >= "#7"

On Windows 10, IIS 10 is bundled and reports an IISVERSIONMAJOR of #10

As this is a string, it fails the >= comparison check, so one cannot proceed.

Since the versions of Windows we target and support already have a version of IIS 7 or higher, we can remove the check.

[jng]

Correction: We'll adjust the check to be (NOT IISVERSIONMAJOR = "#0") as these conditions still require IIS to be present, we can just safely assume that the version will be >= 7

[jng]

Fixed trunk (r9051), 3.1 (r9052), 3.0 (r9053), 2.6 (r9054)