In killproc(), re-add a '--retry 5' to s-s-d when no signal is specified.

In killproc(), re-add a '--retry 5' to s-s-d when no signal is specified.

According to the letter of the LSB:

killproc:"If a signal is specified, (...) the program is sent that signal.
          Otherwise, a SIGTERM followed by a SIGKILL after an unspecified
          number of seconds shall be sent."

According to start-stop-daemon manpage, that's what `--retry 5` does, with `5
seconds` being the `unspecified` of LSB, hence the `--retry 5` is only added
in the case where no signal is specified.

Closes: #650584
Reported-by: Daniel Nelson <torham@connect2.com>
Signed-off-by: Didier Raboud <odyx@debian.org>