fix quartiles of empty histograms
fix quartiles of empty histograms

werpat/MoonGen,scholzd/MoonGen,slyon/MoonGen,pavel-odintsov/MoonGen,emmericp/MoonGen,schoenb/MoonGen,emmericp/MoonGen,kidaa/MoonGen,wenhuizhang/MoonGen,atheurer/MoonGen,slyon/MoonGen,pavel-odintsov/MoonGen,gallenmu/MoonGen,kidaa/MoonGen,gallenmu/MoonGen,atheurer/MoonGen,emmericp/MoonGen,gallenmu/MoonGen,wenhuizhang/MoonGen,schoenb/MoonGen,pavel-odintsov/MoonGen,schoenb/MoonGen,dschoeffm/MoonGen,dschoeffm/MoonGen,NetronomeMoongen/MoonGen,bmichalo/MoonGen,slyon/MoonGen,gallenmu/MoonGen,gallenmu/MoonGen,atheurer/MoonGen,bmichalo/MoonGen,werpat/MoonGen,wenhuizhang/MoonGen,slyon/MoonGen,gallenmu/MoonGen,bmichalo/MoonGen,duk3luk3/MoonGen,gallenmu/MoonGen,werpat/MoonGen,duk3luk3/MoonGen,bmichalo/MoonGen,NetronomeMoongen/MoonGen,dschoeffm/MoonGen,scholzd/MoonGen,gallenmu/MoonGen,duk3luk3/MoonGen,NetronomeMoongen/MoonGen,scholzd/MoonGen,kidaa/MoonGen