Fix case where a machine crashes and won't restart.

sudo /etc/init.d/tron start
 * Starting tron  tron                                                                                                                                                                             Daemon was running as 20990. Remove PID file.

makes no sense - the computer knows the PID file is unused,
it should be able to remove it
I looked DaemonContext code, the PIDFile context is keep open for the duration of daemoncontext itself. Also if you remove the file here, Line 62 will not have a file write to.

Since the file already locked, it will not be easy to remove and relock without possible race condition.  So why not just keep it locked, but seek(0) and truncate(0) reset it to a new file, so line 62 can write current the pid to it.

Daemon library also has its own pidfile implementation, we can switch to that as well I think.