Fix compiler error for Visual Studio 2013+ in ntextapi.h

[maxbelanger]

In winternl.h, the following enumeration conflicts with the one defined in ntextapi.h:

typedef enum _PROCESSINFOCLASS {
    ProcessBasicInformation = 0,
    ProcessDebugPort = 7,
    ProcessWow64Information = 26,
    ProcessImageFileName = 27,
    ProcessBreakOnTermination = 29
} PROCESSINFOCLASS;

The current fix for this that uses an _MSC_VER check (for issue #688 ) but that doesn't fully resolve the issue, as this can happen on Visual Studio 2013 (aka 1800) when using the Windows 8.1 SDK, as I've experienced:

c:\users\max\src\psutil\psutil\arch\windows\ntextapi.h(324) : error C2365: 'ProcessBreakOnTermination' : redefinition; previous definition was 'enumerator'
        C:\Program Files (x86)\Windows Kits\8.1\include\um\winternl.h(308) : see declaration of 'ProcessBreakOnTermination'
c:\users\max\src\psutil\psutil\arch\windows\ntextapi.h(324) : error C2086: '_PROCESSINFOCLASS2 ProcessBreakOnTermination' : redefinition
        c:\users\max\src\psutil\psutil\arch\windows\ntextapi.h(324) : see declaration of 'ProcessBreakOnTermination'

The typical way collisions with this enum are resolved is through underscore-prefixed surrogates (see _ProcessImageFileName). This patch uses the same technique for the ProcessBreakOnTermination item, which should end up with the same value (29). This fixes the build on my machine.

I'm not fully aware of the context surrounding the original issue, so apologies if this doesn't actually solve anything or if I'm missing something obvious :).

[giampaolo]

Merged, thanks.