Remote nagios check

Sometime you need to run a check directly on target server.. I'ts bad but you can't really do something else.

Example : the sybase health stack, 1.9GB with 45min to 1h of installation time.  You really don't want to install that on each of your pollers.

This check just run a (what should be a perfdata compliant) cmd on a remote server.. use it carefully !

```
 #python check_ssh_proxy_perfdata_check.py -i ../shinken-key/shinken@xxx.rsa -u root -P YYY -H xxxsrsp01 --check_path "/usr/lib/check_mk_agent/local/rs_queue_usage"
0 RepServer_Queue_Usage count=0.00;50000;100000;0; OK - Replication Server queue usage : 0 MB (free : 200001 MB)
```