fixes for nova-manage network list  if network has been deleted
fixes for nova-manage network list  if network has been deleted

this fix addresses the  bug #1021810
Currently command 'nova-manage network list' or
'nova-manage fixed list'  will return 'Command failed.' message when
there is no network defined or networks get deleted. This fix combined
with fixes to bug 1025827 will fix both command problem.
also change the print out message so that it can be translated.
code structure changes according to the suggestion from comments.

Change-Id: Id9a1a10217aac971cbbba9db5829c8478892db1a

maheshp/novatest,JianyuWang/nova,fajoy/nova,ruslanloman/nova,CiscoSystems/nova,bclau/nova,berrange/nova,shail2810/nova,BeyondTheClouds/nova,akash1808/nova,gspilio/nova,SUSE-Cloud/nova,Stavitsky/nova,bgxavier/nova,devendermishrajio/nova_test_latest,qwefi/nova,mgagne/nova,luogangyi/bcec-nova,rahulunair/nova,NeCTAR-RC/nova,vmturbo/nova,silenceli/nova,qwefi/nova,jeffrey4l/nova,sacharya/nova,takeshineshiro/nova,akash1808/nova_test_latest,mgagne/nova,maelnor/nova,projectcalico/calico-nova,double12gzh/nova,felixma/nova,NoBodyCam/TftpPxeBootBareMetal,scripnichenko/nova,cyx1231st/nova,alaski/nova,rajalokan/nova,mikalstill/nova,sridevikoushik31/nova,joker946/nova,leilihh/nova,klmitch/nova,eharney/nova,maoy/zknova,petrutlucian94/nova_dev,sebrandon1/nova,sridevikoushik31/openstack,cloudbase/nova-virtualbox,adelina-t/nova,zaina/nova,maheshp/novatest,CEG-FYP-OpenStack/scheduler,shahar-stratoscale/nova,yrobla/nova,gooddata/openstack-nova,gooddata/openstack-nova,viggates/nova,CloudServer/nova,spring-week-topos/nova-week,rahulunair/nova,nikesh-mahalka/nova,DirectXMan12/nova-hacking,eonpatapon/nova,saleemjaveds/https-github.com-openstack-nova,noironetworks/nova,badock/nova,rickerc/nova_audit,maheshp/novatest,eonpatapon/nova,mahak/nova,dims/nova,JioCloud/nova,Yuriy-Leonov/nova,watonyweng/nova,belmiromoreira/nova,adelina-t/nova,mikalstill/nova,varunarya10/nova_test_latest,eharney/nova,isyippee/nova,angdraug/nova,CEG-FYP-OpenStack/scheduler,yatinkumbhare/openstack-nova,citrix-openstack-build/nova,rrader/nova-docker-plugin,ewindisch/nova,shootstar/novatest,vmturbo/nova,cernops/nova,petrutlucian94/nova_dev,yrobla/nova,double12gzh/nova,CiscoSystems/nova,hanlind/nova,tianweizhang/nova,plumgrid/plumgrid-nova,Francis-Liu/animated-broccoli,maelnor/nova,gooddata/openstack-nova,devendermishrajio/nova_test_latest,mandeepdhami/nova,houshengbo/nova_vmware_compute_driver,jianghuaw/nova,JioCloud/nova,tanglei528/nova,cloudbau/nova,sridevikoushik31/nova,usc-isi/nova,BeyondTheClouds/nova,virtualopensystems/nova,tudorvio/nova,cloudbase/nova,thomasem/nova,apporc/nova,NoBodyCam/TftpPxeBootBareMetal,devoid/nova,TieWei/nova,Yusuke1987/openstack_template,NoBodyCam/TftpPxeBootBareMetal,gspilio/nova,dims/nova,cernops/nova,savi-dev/nova,phenoxim/nova,vmturbo/nova,tanglei528/nova,berrange/nova,iuliat/nova,klmitch/nova,joker946/nova,LoHChina/nova,shail2810/nova,fajoy/nova,petrutlucian94/nova,Triv90/Nova,Metaswitch/calico-nova,DirectXMan12/nova-hacking,klmitch/nova,tudorvio/nova,zhimin711/nova,OpenAcademy-OpenStack/nova-scheduler,j-carpentier/nova,silenceli/nova,sridevikoushik31/openstack,paulmathews/nova,bigswitch/nova,Stavitsky/nova,kimjaejoong/nova,ted-gould/nova,devoid/nova,ruslanloman/nova,houshengbo/nova_vmware_compute_driver,cloudbase/nova-virtualbox,spring-week-topos/nova-week,tianweizhang/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,projectcalico/calico-nova,cernops/nova,vladikr/nova_drafts,cloudbase/nova,luogangyi/bcec-nova,imsplitbit/nova,affo/nova,tealover/nova,DirectXMan12/nova-hacking,hanlind/nova,eayunstack/nova,cloudbau/nova,gspilio/nova,iuliat/nova,barnsnake351/nova,leilihh/nova,saleemjaveds/https-github.com-openstack-nova,TwinkleChawla/nova,plumgrid/plumgrid-nova,akash1808/nova_test_latest,Francis-Liu/animated-broccoli,blueboxgroup/nova,cyx1231st/nova,usc-isi/nova,orbitfp7/nova,angdraug/nova,fnordahl/nova,belmiromoreira/nova,tealover/nova,SUSE-Cloud/nova,viggates/nova,savi-dev/nova,tangfeixiong/nova,bgxavier/nova,OpenAcademy-OpenStack/nova-scheduler,klmitch/nova,virtualopensystems/nova,petrutlucian94/nova,badock/nova,watonyweng/nova,alvarolopez/nova,jianghuaw/nova,orbitfp7/nova,sebrandon1/nova,sebrandon1/nova,vmturbo/nova,NewpTone/stacklab-nova,dawnpower/nova,Triv90/Nova,mahak/nova,alexandrucoman/vbox-nova-driver,eayunstack/nova,mahak/nova,JioCloud/nova_test_latest,bigswitch/nova,MountainWei/nova,vladikr/nova_drafts,paulmathews/nova,Tehsmash/nova,Tehsmash/nova,NeCTAR-RC/nova,jianghuaw/nova,openstack/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,leilihh/novaha,hanlind/nova,whitepages/nova,rickerc/nova_audit,imsplitbit/nova,scripnichenko/nova,barnsnake351/nova,aristanetworks/arista-ovs-nova,zhimin711/nova,alvarolopez/nova,nikesh-mahalka/nova,yosshy/nova,tangfeixiong/nova,maoy/zknova,Metaswitch/calico-nova,Yuriy-Leonov/nova,CCI-MOC/nova,alexandrucoman/vbox-nova-driver,mikalstill/nova,ewindisch/nova,ntt-sic/nova,ted-gould/nova,JianyuWang/nova,Juniper/nova,bclau/nova,devendermishrajio/nova,yatinkumbhare/openstack-nova,apporc/nova,whitepages/nova,shahar-stratoscale/nova,fnordahl/nova,Juniper/nova,sridevikoushik31/nova,yrobla/nova,Juniper/nova,TieWei/nova,paulmathews/nova,mmnelemane/nova,zzicewind/nova,savi-dev/nova,TwinkleChawla/nova,yosshy/nova,alaski/nova,raildo/nova,phenoxim/nova,dawnpower/nova,redhat-openstack/nova,openstack/nova,kimjaejoong/nova,dstroppa/openstack-smartos-nova-grizzly,fajoy/nova,zzicewind/nova,openstack/nova,NewpTone/stacklab-nova,dstroppa/openstack-smartos-nova-grizzly,LoHChina/nova,sacharya/nova,CloudServer/nova,NewpTone/stacklab-nova,shootstar/novatest,sridevikoushik31/nova,edulramirez/nova,JioCloud/nova_test_latest,jeffrey4l/nova,mandeepdhami/nova,takeshineshiro/nova,citrix-openstack-build/nova,aristanetworks/arista-ovs-nova,MountainWei/nova,maoy/zknova,devendermishrajio/nova,houshengbo/nova_vmware_compute_driver,affo/nova,akash1808/nova,felixma/nova,blueboxgroup/nova,Juniper/nova,CCI-MOC/nova,varunarya10/nova_test_latest,gooddata/openstack-nova,raildo/nova,noironetworks/nova,leilihh/novaha,Yusuke1987/openstack_template,edulramirez/nova,sridevikoushik31/openstack,aristanetworks/arista-ovs-nova,rajalokan/nova,ntt-sic/nova,isyippee/nova,j-carpentier/nova,rahulunair/nova,rrader/nova-docker-plugin,usc-isi/nova,cloudbase/nova,rajalokan/nova,BeyondTheClouds/nova,dstroppa/openstack-smartos-nova-grizzly,redhat-openstack/nova,rajalokan/nova,zaina/nova,jianghuaw/nova,Triv90/Nova,mmnelemane/nova,thomasem/nova