serverType function fails for "OpenStack Foundation" server type

[cmohorea]

Customer is running on Openstack virtualization:

VMANAGE02:~$ cat /sys/devices/virtual/dmi/id/sys_vendor                                                           
OpenStack Foundation                                                                                                        

and AURA tool fails with:

ERROR:'NoneType' object is not iterable                                                                                     
Traceback (most recent call last):                                                                                          
  File "py3_sure.py", line 2067, in <module>                                                                                
    server_type, server_company  = serverType()                                                                             
TypeError: 'NoneType' object is not iterable  

I fixed it manually with:

	else:
		return 'on-prem', server_type	

but you may want to keep it explicitly in the list in line with the other types.
Some kind of "catch-all" would be nice anyway