fix compiler error "reference to 'system' is ambiguous"
fix compiler error "reference to 'system' is ambiguous"

init.cpp: In function 'bool AppInit2()':
init.cpp:902: error: reference to 'system' is ambiguous
dekkersarjan/netcoin-work,dekkersarjan/netcoin-work,noise23/netcoin,Tepelstreeltje/netcoin,Tepelstreeltje/netcoin,coinkeeper/2015-06-22_19-08_netcoin,Tepelstreeltje/netcoin,Tepelstreeltje/netcoin,dekkersarjan/netcoin-work,netcoinfoundation/netcoin,coinkeeper/2015-06-22_19-08_netcoin,netcoinfoundation/netcoin,Tepelstreeltje/netcoin,netcoinfoundation/netcoin,noise23/netcoin,dekkersarjan/netcoin-work,noise23/netcoin,netcoinfoundation/netcoin,coinkeeper/2015-06-22_19-08_netcoin,netcoinfoundation/netcoin,dekkersarjan/netcoin-work,coinkeeper/2015-06-22_19-08_netcoin,noise23/netcoin