[Users] Dispatcher crash OpenSER

Playing with my dispatcher configuration (openser-1.2.1) I discovered that ds_select_dst() crashes openser when dispatche param ds_use_default is set to 1 and the set from where the destination is picked up contains just one address. This appens because in dispatch.c at row 784 the code is

if(ds_use_default!=0) hash = hash%(_ds_list[idx].nr-1); else hash = hash%_ds_list[idx].nr;

so if ds_use_default is set and the address set has 1 destination the % causes a crash. To avoid this it's enough to modifiy the if statement like:

if (ds_use_default!=0 && _ds_list[idx].nr!=1)

Just my two cents. Regards, Federico