Don't create empty broadpeak file while --broad is not set.
Don't create empty broadpeak file while --broad is not set.

taoliu/MACS,daler/MACS,vd4mmind/MACS,vd4mmind/MACS,vd4mmind/MACS,daler/MACS,taoliu/MACS,taoliu/MACS,daler/MACS