Dbs3 fix serverinfo

Hi @YuyiGuo,

this patch fixes https://github.com/dmwm/DBS/issues/273. The HTTP 500  Error was caused by DBSStatus.py, which is not used anymore and corresponding DBs do not exists anymore.  The serverinfo API is now returning only the deployed DBS version. Since the Status DBs are not used anymore, I have removed all depending code from the current HEAD. 

@YuyiGuo Could you review and merge, please?
@Tiocann Does this provide anything necessary for your availability check?

Thanks,
Manuel