Warn the user when installing on Windows Server 2003 along with XP.
CMake builds are not targeting them, and their support was officially
dropped with Wireshark 1.12.
Update our copy of GetWindowsVersion.nsh with "Alternate Script With
Server Versions" from http://nsis.sourceforge.net/Get_Windows_version.
Change-Id: I762859ea13e1ecd91757eeab360a39d1e6116144
Reviewed-on: https://code.wireshark.org/review/11972
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>