cloudpipe vpns fail to get ip

[Vish Ishaya]

When vpn=true in allocate ip, it attempts to allocate the ip that is reserved in the network. Unfortunately allocate_fixed_ips attempts to ignore reserved ips.

I think this is due to the fact that we are trying to stop users from attempting to select ips like the broadcast address or the network address for vms. My initial suggestion is to remove the line from allocate_fixed_ip that filters based on reserved:

 676 fixed_ip_ref = session.query(models.FixedIp).\
 677 filter(network_or_none).\
 678 filter_by(reserved=False).\
 679 filter_by(deleted=False).\
 680 filter_by(address=address).\
 681 with_lockmode('update').\
 682 first()

Then we can still use reserved to mean, if you're selecting a random ip, ignore these. (Perhaps we should expose a way to reserve ips). If we want to protect users from launching an instance using the network or broadcast ip (i.e. 10.0.0.0 and 10.0.0.255) then perhaps we shoiuld just delete them from the list of fixed ips (or not add them in the first place)