Fix command line corruption on empty option arguments

Fixes #33

init/postsrsd.systemd.in

 Environment=SRS_DOMAIN=localhost.localdomain
 Environment=SRS_EXCLUDE_DOMAINS=
 EnvironmentFile=@CONFIG_DIR@/@PROJECT_NAME@
-ExecStart=@CMAKE_INSTALL_PREFIX@/sbin/@POSTSRSD@ -f"${SRS_FORWARD_PORT}" -r"${SRS_REVERSE_PORT}" -d"${SRS_DOMAIN}" -s"${SRS_SECRET}" -a"${SRS_SEPARATOR}" -u"${RUN_AS}" -c"${CHROOT}" -X"${SRS_EXCLUDE_DOMAINS}"
+ExecStart=@CMAKE_INSTALL_PREFIX@/sbin/@POSTSRSD@ -f "${SRS_FORWARD_PORT}" -r "${SRS_REVERSE_PORT}" -d "${SRS_DOMAIN}" -s "${SRS_SECRET}" -a "${SRS_SEPARATOR}" -u "${RUN_AS}" -c "${CHROOT}" -X "${SRS_EXCLUDE_DOMAINS}"
 Restart=always
 
 [Install]

init/postsrsd.sysv-lsb.in

 		--pidfile $PIDFILE \
 		--name $NAME \
 		--startas $DAEMON \
-		-- -f"$SRS_FORWARD_PORT" -r"$SRS_REVERSE_PORT" -d"$SRS_DOMAIN" -s"$SRS_SECRET" -a "$SRS_SEPARATOR" -u"$RUN_AS" -p"$PIDFILE" -c"$CHROOT" -X"$SRS_EXCLUDE_DOMAINS" -D
+		-- -f "$SRS_FORWARD_PORT" -r "$SRS_REVERSE_PORT" -d "$SRS_DOMAIN" -s "$SRS_SECRET" -a "$SRS_SEPARATOR" -u "$RUN_AS" -p "$PIDFILE" -c "$CHROOT" -X "$SRS_EXCLUDE_DOMAINS" -D
 	then
 	    log_end_msg 0
 	else

init/postsrsd.sysv-redhat.in

 do_start()
 {
 	echo -n "Starting $DESC: "
-	daemon $DAEMON -f"$SRS_FORWARD_PORT" -r"$SRS_REVERSE_PORT" -d"$SRS_DOMAIN" -s"$SRS_SECRET" \
-	               -u"$RUN_AS" -p"$PIDFILE" -a "$SRS_SEPARATOR" -c"$CHROOT" -X"$SRS_EXCLUDE_DOMAINS" -D
+	daemon $DAEMON -f "$SRS_FORWARD_PORT" -r "$SRS_REVERSE_PORT" -d "$SRS_DOMAIN" -s "$SRS_SECRET" \
+	               -u "$RUN_AS" -p "$PIDFILE" -a "$SRS_SEPARATOR" -c "$CHROOT" -X "$SRS_EXCLUDE_DOMAINS" -D
 	RETVAL=$?
 	echo
     	[ $RETVAL -eq 0 ] && touch /var/lock/subsys/$NAME

init/postsrsd.upstart.in

 	SRS_DOMAIN=`postconf -h mydomain || true`
 	SRS_EXCLUDE_DOMAINS=
 	. "@CONFIG_DIR@/@PROJECT_NAME@"
-	exec @CMAKE_INSTALL_PREFIX@/sbin/@POSTSRSD@ -f"$SRS_FORWARD_PORT" -r"$SRS_REVERSE_PORT" -d"$SRS_DOMAIN" -s"$SRS_SECRET" -a "$SRS_SEPARATOR" -u"$RUN_AS" -c"$CHROOT" -X"$SRS_EXCLUDE_DOMAINS"
+	exec @CMAKE_INSTALL_PREFIX@/sbin/@POSTSRSD@ -f "$SRS_FORWARD_PORT" -r "$SRS_REVERSE_PORT" -d "$SRS_DOMAIN" -s "$SRS_SECRET" -a "$SRS_SEPARATOR" -u "$RUN_AS" -c "$CHROOT" -X "$SRS_EXCLUDE_DOMAINS"
 end script