Add gnocchi::storage::s3::s3_bucket_prefix into s3 storage configuration
Add gnocchi::storage::s3::s3_bucket_prefix into s3 storage configuration

Change-Id: I9b0b61dc6d0b913b16876841baf2ed0b94f1fd77
Closes-Bug: #1822111

openstack/puppet-gnocchi,openstack/puppet-gnocchi