disable confusing [ERROR] printing on retcode!=0 where not relevant

This is a small addition to make the output look clearer.

```
[ERROR  ] Command '/sbin/service nrpe status' failed with return code: 3
[ERROR  ] output: nrpe is stopped
[ERROR  ] Command '/sbin/service xinetd status' failed with return code: 3
[ERROR  ] output: xinetd is stopped
[ERROR  ] Command '/sbin/service haproxy status' failed with return code: 3
[ERROR  ] output: haproxy is stopped
```

on the ```service.status nrpe``` it will give:

```
[INFO    ] Executing command '/sbin/service nrpe status' in directory '/root'
[INFO    ] output: nrpe is stopped
local:
    False
```


vs
```
[INFO    ] Executing command '/sbin/service nrpe status' in directory '/root'
[ERROR   ] Command '/sbin/service nrpe status' failed with return code: 3
[ERROR   ] output: nrpe is stopped
local:
    False
```

it also affects ```service.enable``` making it easier to read where the error is.
```
[INFO    ] Executing command '/sbin/chkconfig --list haproxya' in directory '/root'
[INFO    ] output: error reading information on service haproxya: No such file or directory
[INFO    ] Executing command '/sbin/chkconfig --add haproxya' in directory '/root'
[ERROR   ] Command '/sbin/chkconfig --add haproxya' failed with return code: 1
[ERROR   ] output: error reading information on service haproxya: No such file or directory
[ERROR   ] Unable to add initscript "haproxya" to chkconfig
local:
    False
```

vs

```
[INFO    ] Executing command '/sbin/chkconfig --list haproxya' in directory '/root'
[ERROR   ] Command '/sbin/chkconfig --list haproxya' failed with return code: 1
[ERROR   ] output: error reading information on service haproxya: No such file or directory
[INFO    ] Executing command '/sbin/chkconfig --add haproxya' in directory '/root'
[ERROR   ] Command '/sbin/chkconfig --add haproxya' failed with return code: 1
[ERROR   ] output: error reading information on service haproxya: No such file or directory
[ERROR   ] Unable to add initscript "haproxya" to chkconfig
local:
    False
```