journalctl: fix output when --until is used with --lines

journalctl: fix output when --until is used with --lines

Before this commit, when --lines is specified, we jump to the tail and
search afterwards from there, thus breaking --until if used together.

After this commit:
If both --until and any of --reverse and --lines is specified, things get
a little tricky. We seek to the place of --until first. If only --reverse or
--reverse and --lines is specified, we search backwards and let the output
counter handle --lines for us. If only --lines is used, we just jump backwards
arg_lines and search afterwards from there.