Revert "Removed 'Do nothing' logic from cta::server::Daemon which unwantedly...

Revert "Removed 'Do nothing' logic from cta::server::Daemon which unwantedly kicks in if systemd is used"

This reverts commit 462959d4.

The current pipeline in the GitLab CI keeps failing to complete
the "init" pod's work.  The same Docker image is used on
stevedevctai.cern.ch to successfully run systest.sh -n ctatest.

The GitLab CI does not provide any logs from the "init" pod and
therefore cannot be debugged.

This revert is a desperate attempt at fixing ithe problem.  If it
does work then it means the GitLab CI is benefiting from cta-taped
remaining as the root user.

common/threading/Daemon.cpp

@@ -78,6 +78,11 @@ void cta::server::Daemon::setCommandLineHasBeenParsed(const bool foreground)
 //------------------------------------------------------------------------------
 void cta::server::Daemon::daemonizeIfNotRunInForegroundAndSetUserAndGroup(const std::string &userName,
   const std::string &groupName) {
+  // Do nothing if already a daemon
+  if (1 == getppid())  {
+    return;
+  }
+
   // If the daemon is to be run in the background
   if (!m_foreground) {
     m_log.prepareForFork();