remove obsolete s3 conf from nova.conf
remove obsolete s3 conf from nova.conf

Change-Id: If0b42c647382b739ee4f1d98ea0394ec7b171ebf

group-policy/devstack,openstack-dev/devstack,noironetworks/devstack,dtroyer/devstack,bswartz/devstack,dtroyer/devstack,bswartz/devstack,group-policy/devstack,richliu/devstack,richliu/devstack,nawawi/openstack,nawawi/openstack,noironetworks/devstack,openstack-dev/devstack