main: also redirect Fatal logger to syslog on daemonization
main: also redirect Fatal logger to syslog on daemonization

The messages would still be collected via gocryptfs-logger,
but let's do it right.

Before:

  Oct 17 21:58:12 brikett gocryptfs[9926]: testing info
  Oct 17 21:58:12 brikett gocryptfs[9926]: testing warn
  Oct 17 21:58:12 brikett gocryptfs-9926-logger[9935]: testing fatal

After:

  Oct 17 22:00:53 brikett gocryptfs[10314]: testing info
  Oct 17 22:00:53 brikett gocryptfs[10314]: testing warn
  Oct 17 22:00:53 brikett gocryptfs[10314]: testing fatal

rfjakob/gocryptfs,rfjakob/gocryptfs,rfjakob/gocryptfs,rfjakob/gocryptfs