core: remove sysv_console option

This option never made much sense. It was originally intended to make
sure that the usual startup output of sysv scripts goes to the terminal.
However, since SysV scripts started from a terminal would not output to
that terminal, but rather /dev/console this effect was more often than
not actually taking place. Nowadays systemd has much nicer boot time
status output than SysV which makes the sysv output redundant. Finally,
all output of services goes to the journal anyway, and is not lost.

Hence, let's drop this option, and simplify things a bit.

man/kernel-command-line.xml

@@ -80,7 +80,6 @@
                                 <term><varname>systemd.crash_chvt=</varname></term>
                                 <term><varname>systemd.confirm_spawn=</varname></term>
                                 <term><varname>systemd.show_status=</varname></term>
-                                <term><varname>systemd.sysv_console=</varname></term>
                                 <term><varname>systemd.log_target=</varname></term>
                                 <term><varname>systemd.log_level=</varname></term>
                                 <term><varname>systemd.log_color=</varname></term>