script: --quiet option is not quiet.

Specifying 'script --quiet ...' still produces the 'Script started'
message in the typescript file. The --quiet option implies that the
script program should not log any of its output to the typescript file.

Originally reported at:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=693966

Signed-off-by: Andreas Henriksson <andreas@fatal.se>
script: silence the done message on --quiet as well

Apparently James Hunts patch (which he provided a long time
ago) is no longer covering it all.

This followup patch also silences the "Script done ..." message
when --quiet is used.

Signed-off-by: Andreas Henriksson <andreas@fatal.se>
script: clean up code to genenrate Star/Done messages

Signed-off-by: Karel Zak <kzak@redhat.com>