Ref T13321. Since "just use the process list" is looking a whole lot more attractive than PID files, improve the robustness of the query when identifying overseers.
Currently, we could incorrectly identify processes like "grep phd-daemon" as overseers.
To fix this, don't just look for "\bphd-daemon\b" anywhere in the process title: require the first argument be a path that ends in "phd-daemon", or the first two arguments end in "php phd-daemon".