When RangeEnd is given, a.end = RangeEnd+1.
If when getSearchRange() is called and lastReservedIP equals
RangeEnd, a.nextIP() only compares lastReservedIP (which in this
example is RangeEnd) against a.end (which in this example is
RangeEnd+1) and they clearly don't match, so a.nextIP() returns
start=RangeEnd+1 and end=RangeEnd.
Get() happily allocates RangeEnd+1 because it only compares 'cur'
to the end returned by getSearchRange(), not to a.end, and thus
allocates past RangeEnd.
Since a.end is inclusive (eg, host-local will allocate a.end) the
fix is to simply set a.end equal to RangeEnd.
This changes the ip allocation logic to round robin. Before this, host-local IPAM searched for available IPs from start of subnet. Hence it tends to allocate IPs that had been used recently. This is not ideal since it may cause collisions.
