Added HSRP support for NXOS and fixed check-config

The HSRP for Nexus is a simple two line addition in plugins-scripts/Classes/Cisco/NXOS.pm
It has been tested on a Cisco N3K-C3548P-10G

I couldn't understand why the check-config was implemented the way it was (especially what the use of ccmHistoryRunningLastSaved was) so I rewrote it to what I think is useful.
Basically I just test ccmHistoryStartupLastChanged against ccmHistoryRunningLastChanged.

See https://gist.github.com/mhoogveld/9827493 for a description of what and when OID's change

Hope you find this helpful