#665 win32api GetNativeSystemInf() crashes Python interpreter - fix provided

[Marqo09]

This issue is caused by a one like copy/paste error in win32apimodule.cpp on line 2192.

CHECK_PFN(SetSystemPowerState); should be CHECK_PFN(GetNativeSystemInfo);

When called on Windows 2000 (where GetNativeSystemInfo does not exist), CHECK_PFN returns successfully since SetSystemPowerState exists. The function goes on to call GetNativeSystemInfo which is NULL and the access violation in unmanaged code crashes the whole process.

[Roger Upole]

Thanks, fix committed