fixes this error, since device_port_power.power can be null:
Argument "" isn't numeric in numeric gt (>) at /home/netdisco/perl5/lib/perl5/auto/share/dist/App-Netdisco/views/ajax/device/ports.tt line 251.
currently only seen on cisco sb switches, which do have all other columns filled in
ip | port | module | admin | status | class | power
---------------+------+--------+-------+------------+--------+-------
10.40.254.150 | fa2 | 1 | true | otherFault | class3 |
10.40.254.150 | fa16 | 1 | true | searching | class3 |
10.40.254.150 | fa3 | 1 | true | searching | class3 |
...
d1a1235c85