Increase default swift storage
Increase default swift storage

Swift storage is used as glance image back-end. Tempest have cinder to
uploads 1 GiB image from cinder in twice.

In parallel execution in cause an issue, bacuse the current default size is
1_000_000 KiB.

Increasing the default swit storage size from 1_000_000 KiB 4_000_000
KiB when tempest is enabled.

Fixing bug 1225664

Change-Id: Iccd6368e4df71abb5ccfe7d361c64d86e1071d35

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