Wait half a minute for a new started cupsd:
Wait half a minute for a new started cupsd is necessary because
when a client-only config is switched to a "get Browsing info" config
the BrowseInterval in cupsd.conf on remote CUPS servers is by default 30 seconds
so that the local cupsd should listen at least 31 seconds to get Browsing info
before e.g. the Overview dialog can be shown with the right current queues.