wined3d: Make CreateFakeGLContext thread safe. [try 2]

[Robert Shearman]

Jan Zerebecki wrote:
>  
> +    LeaveCriticalSection(&wined3d_fake_gl_context_cs);
> +    LEAVE_GL();
>   
...
>      LEAVE_GL();
> +    LeaveCriticalSection(&wined3d_fake_gl_context_cs);
>      return FALSE;
>  }

You can't lock or unlock in different orders as this will create subtle 
races that could result in deadlocks.

-- 
Rob Shearman