I realised that my DMB<->DMB sync code has the property that the

I realised that my DMB<->DMB sync code has the property that the
amount of network traffic grows as the square of the number of
workgroups. It probably wouldn't have caused problems but to be safe I
changed the code to use random() to decrease the probability of a
DMB<->DMB sync in proportion to the number of known workgroups. This
keeps the nice browse connectivity while making the traffic rise only
linearly with the number of workgroups.