Service: set explicit service timeout instead of passing undef with sysv

Deal with warnings like
```
[INFO] running component: metaconfig
---------------------------------------------------------
updated /etc/logstash-forwarder
changed mode(00640) of /etc/logstash-forwarder
Use of uninitialized value in concatenation (.) or string at /usr/lib/perl/CAF/Process.pm line 174.
Use of uninitialized value $timeout in addition (+) at /usr/lib/perl/LC/Process.pm line 668.
[INFO] configure on component metaconfig executed, 0 errors, 0 warnings
```