Fix for "Rogue pidfile found!"

 modify the minecraft bash script
1. remove the pid file after shutdown minecraft
2. check of rogue file does not check then the shutdown in work
3. check the permissions and inform the user
4. the rogue file warning comes once, not on every work check. the problem was when the file is not writeable, or the jvm can not start and stop instant. ( start parameters ) the old file was not overriden/delete and the check goes to the old pid.