Fixed pyflakes warnings generated in topo/misc/lancext.py
Fixed pyflakes warnings generated in topo/misc/lancext.py

mjabri/topographica,Tasignotas/topographica_mirror,Tasignotas/topographica_mirror,Tasignotas/topographica_mirror,mjabri/topographica,mjabri/topographica,ioam/topographica,ioam/topographica,mjabri/topographica,ioam/topographica,Tasignotas/topographica_mirror,ioam/topographica,mjabri/topographica,Tasignotas/topographica_mirror,ioam/topographica