Remove dead code in command processing
While reviewing #2693 (closed), @andrei discovered that adding log messages in ControlledDhcpv4Srv::processCommand() section that handles libreload doesn't actually gets triggered when the command are sent over CA or directly over UNIX socket. This should be investigated further. Perhaps processCommand() is no longer needed?
See background and details here: !1895 (877d1cfa, comment 345720)