Fallback coverage backdoor telnet connection to lo
Fallback coverage backdoor telnet connection to lo

This commit adds a fallback condition for the telnet connection.
If trying to establish a connection to the backdoor fails with
ECONNREFUSED the extension will then try to connect to the same
port on the lo device. Eventlet backdoors currently open on the
lo interface and this is to cover the common (and CI) use case
where the hostname doesn't resolve to 127.0.0.1.

Using the fallback was done to avoid adding a new config option
to specify that the hostname that is in the DB for the service
doesn't resolve to the lo device, and that the extension should
use just use localhost.

Change-Id: I0321db68cbccf0cddf13d91a77dfb744bb456d87

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