gui.topology.py: Minor bug fix
gui.topology.py: Minor bug fix

jacobq/csci5221-viro-project,chenyuntc/pox,andiwundsam/_of_normalize,kavitshah8/SDNDeveloper,kulawczukmarcin/mypox,andiwundsam/_of_normalize,noxrepo/pox,chenyuntc/pox,diogommartins/pox,diogommartins/pox,adusia/pox,jacobq/csci5221-viro-project,adusia/pox,pthien92/sdn,xAKLx/pox,waltznetworks/pox,waltznetworks/pox,carlye566/IoT-POX,noxrepo/pox,PrincetonUniversity/pox,xAKLx/pox,xAKLx/pox,carlye566/IoT-POX,xAKLx/pox,jacobq/csci5221-viro-project,diogommartins/pox,andiwundsam/_of_normalize,chenyuntc/pox,carlye566/IoT-POX,adusia/pox,pthien92/sdn,xAKLx/pox,kpengboy/pox-exercise,kulawczukmarcin/mypox,jacobq/csci5221-viro-project,noxrepo/pox,pthien92/sdn,adusia/pox,MurphyMc/pox,diogommartins/pox,VamsikrishnaNallabothu/pox,MurphyMc/pox,diogommartins/pox,adusia/pox,VamsikrishnaNallabothu/pox,kavitshah8/SDNDeveloper,pthien92/sdn,kpengboy/pox-exercise,PrincetonUniversity/pox,kpengboy/pox-exercise,MurphyMc/pox,kpengboy/pox-exercise,kulawczukmarcin/mypox,VamsikrishnaNallabothu/pox,andiwundsam/_of_normalize,PrincetonUniversity/pox,waltznetworks/pox,waltznetworks/pox,kulawczukmarcin/mypox,waltznetworks/pox,kavitshah8/SDNDeveloper,chenyuntc/pox,carlye566/IoT-POX,noxrepo/pox,denovogroup/pox,kulawczukmarcin/mypox,kavitshah8/SDNDeveloper,VamsikrishnaNallabothu/pox,PrincetonUniversity/pox,denovogroup/pox,kpengboy/pox-exercise,pthien92/sdn,VamsikrishnaNallabothu/pox,jacobq/csci5221-viro-project,denovogroup/pox,carlye566/IoT-POX,denovogroup/pox,MurphyMc/pox,chenyuntc/pox,denovogroup/pox,MurphyMc/pox,PrincetonUniversity/pox