The PTY approach caused isatty() to return true for services using
the log directive, triggering programs like fprintd (using glib) to
emit ANSI escape codes and other TTY-specific formatting in syslog.
Using a standard pipe ensures isatty() correctly returns false, so
programs produce plain text output suitable for logging.
For services that require line-buffered output, users can wrap the
command with `stdbuf -oL` as documented in doc/config/logging.md.
Fixes#455
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>