Add error checks to provider net and subnet creation
Add error checks to provider net and subnet creation

Error checks are added to detect provider network and subnet
creation.

Closes-Bug: #1423766
Change-Id: I4d4323d1c3159f84ce3d19924a569b153038d542

pacinete/devstack,neerja28/Devstack_GlusterFS,NaokiMiyata/devstack,dirkmueller/devstack,sc68cal/devstack,prithivm/branch01,andrewrothstein/devstack,BSJAIN92/OpenStack,bq-xiao/devstack,bljgaurav/openstack-test,sequenceiq/devstack,promptworks/devstack,sequenceiq/devstack,kplus/devstack-moonshot,group-policy/devstack,dtroyer/devstack,bljgaurav/openstack-test,HPCHub/devstack,rushiagr/devstack,Mahito/devstack,vsham20/devstack,LoHChina/devstack,promptworks/devstack,bigswitch/devstack,herrsechs/devstack,samgoon/devstack,pczerkas/devstack,thomasem/devstack,mc2014/devstack,olivierlemasle/devstack,atulpatil301/devstack,mmasaki/devstack,CloudServer/devstack,nuxeh/devstack,flavio-fernandes/devstack,mmasaki/devstack,CloudServer/devstack,samgoon/devstack,thomasem/devstack,costingalan/devstack,nawawi/openstack,mssumanth/devstack,andrewrothstein/devstack,flavio-fernandes/devstack,upadhyay-prashant/devstack,TwinkleChawla/devstack,dirkmueller/devstack,wenhuizhang/devstack,mssumanth/devstack,prithivm/branch01,wenhuizhang/devstack,pombredanne/devstack,sc68cal/devstack,richliu/devstack,eharney/devstack,openstack-dev/devstack,upadhyay-prashant/devstack,BSJAIN92/OpenStack,HPCHub/devstack,ozamiatin/devstack,liuquansheng47/devstack,parul24/devstack,avvocatodemarchis/devstack,mc2014/devstack,Mahito/devstack,costingalan/devstack,pczerkas/devstack,varunarya10/devstack,group-policy/devstack,ozamiatin/devstack,bswartz/devstack,olivierlemasle/devstack,j4/devstack,liuquansheng47/devstack,vsham20/devstack,eharney/devstack,bswartz/devstack,noironetworks/devstack,vishnugonela/devstack,j4/devstack,herrsechs/devstack,varunarya10/devstack,richliu/devstack,nawawi/openstack,pacinete/devstack,NaokiMiyata/devstack,nuxeh/devstack,pombredanne/devstack,neerja28/Devstack_GlusterFS,openstack-dev/devstack,parul24/devstack,LoHChina/devstack,kplus/devstack-moonshot,bigswitch/devstack,bq-xiao/devstack,noironetworks/devstack,rushiagr/devstack,vishnugonela/devstack,dtroyer/devstack,atulpatil301/devstack,avvocatodemarchis/devstack,TwinkleChawla/devstack