Configuration to check if hvm is enabled in XS

[Koushik Das]

I found the following piece of code in XCPServerDiscoverer.java (configure() 
method)

        value = _params.get("xen.check.hvm");
        _checkHvm = value == null ? true : Boolean.parseBoolean(value);

Currently there is no configuration in the database with that name and so 
_checkHvm is always true. This requires that XS host has hvm enabled on it 
before it can be added through CS. Wanted to check why this configuration got 
added? Also don't see any such check for other HVs.

Thanks,
Koushik