"Publish workstation" and "Publish hinfo" export some metadata about the machine which aren't necessary for normal operations. If used to monitor availability of remote machines, such as in a computer lab, system administrators could enable them remotely.
Created attachment 902964 [details] 0001-Disable-publish-workstation-and-publish-hinfo-by-def.patch
Fixed in avahi-0.6.31-28 for fc21 and fc22.