Check_MK Werk 6410: Determine the parent process more reliably

ID: 6410 Title: Determine the parent process more reliably Component: Site Management Level: 1 Class: Bug fix Version: 1.6.0i1 Previously, the parent process was determined by parsing /proc/{PID}/stat and columns where assumed to be separated by space. This was unreliable because the filename in the second column may contain a space as well. If omd was issued e.g. from tmux the process name "tmux: server" was used. This resulted in a traceback during e.g. omd rm. Now the psutil module is used to determine the parent process.