Handle situation when key not memcached
Handle situation when key not memcached

LOG a warning message if the key not memcached successful. This will
happen if memcached module is used but the memcached servers are not
reachable.

Change-Id: Ia3c51fe8fc82060586a014f5cb1083d5695ab455
Closes-bug: 1213660

tangfeixiong/nova,Francis-Liu/animated-broccoli,zaina/nova,akash1808/nova_test_latest,tudorvio/nova,NeCTAR-RC/nova,vmturbo/nova,dims/nova,Juniper/nova,gooddata/openstack-nova,isyippee/nova,shail2810/nova,mgagne/nova,double12gzh/nova,orbitfp7/nova,cernops/nova,CEG-FYP-OpenStack/scheduler,klmitch/nova,jianghuaw/nova,hanlind/nova,mikalstill/nova,petrutlucian94/nova,rajalokan/nova,yatinkumbhare/openstack-nova,tangfeixiong/nova,noironetworks/nova,dims/nova,rahulunair/nova,saleemjaveds/https-github.com-openstack-nova,vmturbo/nova,jeffrey4l/nova,klmitch/nova,phenoxim/nova,vmturbo/nova,watonyweng/nova,tudorvio/nova,watonyweng/nova,zzicewind/nova,CloudServer/nova,takeshineshiro/nova,mgagne/nova,alexandrucoman/vbox-nova-driver,openstack/nova,maelnor/nova,alvarolopez/nova,iuliat/nova,apporc/nova,projectcalico/calico-nova,varunarya10/nova_test_latest,thomasem/nova,Juniper/nova,virtualopensystems/nova,badock/nova,cloudbase/nova,openstack/nova,jianghuaw/nova,Juniper/nova,tealover/nova,akash1808/nova_test_latest,JioCloud/nova,JianyuWang/nova,cernops/nova,mahak/nova,rajalokan/nova,Yusuke1987/openstack_template,mahak/nova,fnordahl/nova,blueboxgroup/nova,barnsnake351/nova,akash1808/nova,nikesh-mahalka/nova,alaski/nova,Juniper/nova,ruslanloman/nova,affo/nova,MountainWei/nova,iuliat/nova,eonpatapon/nova,affo/nova,dawnpower/nova,j-carpentier/nova,vladikr/nova_drafts,devendermishrajio/nova_test_latest,mikalstill/nova,rahulunair/nova,bigswitch/nova,LoHChina/nova,vladikr/nova_drafts,yatinkumbhare/openstack-nova,CCI-MOC/nova,Francis-Liu/animated-broccoli,eonpatapon/nova,tianweizhang/nova,maelnor/nova,whitepages/nova,mikalstill/nova,CEG-FYP-OpenStack/scheduler,alexandrucoman/vbox-nova-driver,angdraug/nova,NeCTAR-RC/nova,bgxavier/nova,joker946/nova,gooddata/openstack-nova,adelina-t/nova,fnordahl/nova,TwinkleChawla/nova,raildo/nova,tealover/nova,jeffrey4l/nova,ruslanloman/nova,hanlind/nova,shail2810/nova,belmiromoreira/nova,jianghuaw/nova,berrange/nova,redhat-openstack/nova,klmitch/nova,ted-gould/nova,redhat-openstack/nova,vmturbo/nova,cyx1231st/nova,virtualopensystems/nova,bigswitch/nova,berrange/nova,scripnichenko/nova,mmnelemane/nova,jianghuaw/nova,gooddata/openstack-nova,barnsnake351/nova,MountainWei/nova,rahulunair/nova,saleemjaveds/https-github.com-openstack-nova,Stavitsky/nova,cloudbase/nova-virtualbox,JioCloud/nova_test_latest,Metaswitch/calico-nova,belmiromoreira/nova,eayunstack/nova,Tehsmash/nova,apporc/nova,cloudbase/nova,CloudServer/nova,devendermishrajio/nova,zhimin711/nova,adelina-t/nova,mandeepdhami/nova,viggates/nova,felixma/nova,zzicewind/nova,felixma/nova,kimjaejoong/nova,alvarolopez/nova,sebrandon1/nova,joker946/nova,phenoxim/nova,BeyondTheClouds/nova,edulramirez/nova,mahak/nova,Tehsmash/nova,hanlind/nova,raildo/nova,j-carpentier/nova,Metaswitch/calico-nova,devendermishrajio/nova,mandeepdhami/nova,BeyondTheClouds/nova,JioCloud/nova_test_latest,viggates/nova,yosshy/nova,cyx1231st/nova,dawnpower/nova,zaina/nova,projectcalico/calico-nova,tianweizhang/nova,JianyuWang/nova,devendermishrajio/nova_test_latest,sebrandon1/nova,klmitch/nova,openstack/nova,BeyondTheClouds/nova,CCI-MOC/nova,Stavitsky/nova,silenceli/nova,bgxavier/nova,scripnichenko/nova,tanglei528/nova,mmnelemane/nova,varunarya10/nova_test_latest,noironetworks/nova,badock/nova,nikesh-mahalka/nova,LoHChina/nova,ted-gould/nova,akash1808/nova,cernops/nova,petrutlucian94/nova,thomasem/nova,Yusuke1987/openstack_template,whitepages/nova,JioCloud/nova,double12gzh/nova,gooddata/openstack-nova,cloudbase/nova,alaski/nova,silenceli/nova,sebrandon1/nova,edulramirez/nova,takeshineshiro/nova,blueboxgroup/nova,zhimin711/nova,kimjaejoong/nova,isyippee/nova,TwinkleChawla/nova,rajalokan/nova,angdraug/nova,eayunstack/nova,orbitfp7/nova,rajalokan/nova,tanglei528/nova,cloudbase/nova-virtualbox,yosshy/nova