fix compiler error for MSVC2015 (unscoped enum C++11 problem)
fix compiler error for MSVC2015 (unscoped enum C++11 problem)

0-wiz-0/psutil,mrjefftang/psutil,0-wiz-0/psutil,giampaolo/psutil,mrjefftang/psutil,giampaolo/psutil,mrjefftang/psutil