mxservicectl: Continue after systemctl start error

If `systemctl start SERVICE` fails for whatever reasons,
mxservicectl, which is running with the -e option, immediately
exits with a non-zero exit status and doesn't attempt to
start later mxstartup services.

The exist status will also be the final exit status
of mxstartupctl. If mxstartupctl has been called from
mxstartup-classic.service, the service startup is regarded
as a failure and systemd kills all processes in the group,
which terminates all previously started mxstartup services.

Ignore exit status from `systemctl start SERVICE'.

mxservicectl

@@ -21,7 +21,7 @@ function mxsrv_start_one() {
 
    case "${MX_SRV_SCRIPT}" in
        *.service)
-           systemctl start "${MX_SRV_SCRIPT}"
+           systemctl start "${MX_SRV_SCRIPT}" || true
            ;;
        *)
            su - ${MX_SRV_USER} -c "${MX_SRV_SCRIPT} start" &
@@ -43,7 +43,7 @@ function mxsrv_stop_one() {
 
    case "${MX_SRV_SCRIPT}" in
        *.service)
-           systemctl stop "${MX_SRV_SCRIPT}"
+           systemctl stop "${MX_SRV_SCRIPT}" || true
            ;;
        *)
            su - ${MX_SRV_USER} -c "${MX_SRV_SCRIPT} stop" &