service: do not let a script timeout take PID 1 with it

A stop: or reload: script written with a timeout killed Finit at
config load:

    service stop:5,/bin/true service.sh -- Boom

parse_script() takes the timeout as a pointer and the caller decides
whether it wants one.  However, both stop: and reload: scripts so far
have no timeout, i.e., NULL.  Guard the branch that reads a leading
number.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/Makefile.am

@@ -33,6 +33,7 @@ EXTRA_DIST		+= bootstrap-crash.sh
 EXTRA_DIST		+= cond-start-task.sh
 EXTRA_DIST		+= conf-format.sh
 EXTRA_DIST		+= conf-template.sh
+EXTRA_DIST		+= script-timeout.sh
 EXTRA_DIST		+= crashing.sh
 EXTRA_DIST		+= dep-chain-reload.sh
 EXTRA_DIST		+= depserv.sh
@@ -79,6 +80,7 @@ TESTS			+= bootstrap-crash.sh
 TESTS			+= cond-start-task.sh
 TESTS			+= conf-format.sh
 TESTS			+= conf-template.sh
+TESTS			+= script-timeout.sh
 TESTS			+= crashing.sh
 TESTS			+= dep-chain-reload.sh
 TESTS			+= depserv.sh