Fix marconi's storage setting for MongoDB
Fix marconi's storage setting for MongoDB

The storage driver should be set to mongodb and the driver's uri to the
mongodb:// uri.

Change-Id: I6193a5d78f6cd7283b4e3b1831978883b9e99b06

tianweizhang/devstack,pombredanne/devstack,thomasem/devstack,HPCHub/devstack,prithivm/branch01,rushiagr/devstack,samgoon/devstack,liuquansheng47/devstack,pacinete/devstack,mc2014/devstack,Mahito/devstack,richliu/devstack,pczerkas/devstack,dtroyer/devstack,avvocatodemarchis/devstack,ozamiatin/devstack,bswartz/devstack,TwinkleChawla/devstack,pczerkas/devstack,nawawi/openstack,group-policy/devstack,HPCHub/devstack,neerja28/Devstack_GlusterFS,costingalan/devstack,prithivm/branch01,dirkmueller/devstack,nawawi/openstack,kplus/devstack-moonshot,NaokiMiyata/devstack,mmasaki/devstack,samgoon/devstack,sc68cal/devstack,bljgaurav/openstack-test,promptworks/devstack,bigswitch/devstack,bswartz/devstack,mssumanth/devstack,parul24/devstack,noironetworks/devstack,TwinkleChawla/devstack,openstack-dev/devstack,BSJAIN92/OpenStack,BSJAIN92/OpenStack,openstack-dev/devstack,ozamiatin/devstack,virtualopensystems/devstack,mssumanth/devstack,sc68cal/devstack,wenhuizhang/devstack,costingalan/devstack,CloudServer/devstack,LoHChina/devstack,herrsechs/devstack,j4/devstack,olivierlemasle/devstack,Mahito/devstack,rushiagr/devstack,flavio-fernandes/devstack,innodee/openstackk,bigswitch/devstack,nuxeh/devstack,JioCloud/devstack,bq-xiao/devstack,LoHChina/devstack,sequenceiq/devstack,parul24/devstack,noironetworks/devstack,srics/devstack,bljgaurav/openstack-test,mmasaki/devstack,liuquansheng47/devstack,pombredanne/devstack,kplus/devstack-moonshot,wenhuizhang/devstack,group-policy/devstack,olivierlemasle/devstack,tianweizhang/devstack,varunarya10/devstack,promptworks/devstack,williamthegrey/devstack,andrewrothstein/devstack,affo/devstack,neerja28/Devstack_GlusterFS,eharney/devstack,atulpatil301/devstack,j4/devstack,vishnugonela/devstack,andrewrothstein/devstack,sequenceiq/devstack,vsham20/devstack,avvocatodemarchis/devstack,eharney/devstack,upadhyay-prashant/devstack,pacinete/devstack,thomasem/devstack,nuxeh/devstack,NaokiMiyata/devstack,varunarya10/devstack,richliu/devstack,eshnil2000/devstack,Juniper/devstack,atulpatil301/devstack,affo/devstack,bq-xiao/devstack,vishnugonela/devstack,mc2014/devstack,flavio-fernandes/devstack,dtroyer/devstack,upadhyay-prashant/devstack,dirkmueller/devstack,CloudServer/devstack,herrsechs/devstack,jamielennox/devstack,vsham20/devstack