Delete the duplicate words in  cephfs_driver.rst
@@ -526,7 +526,7 @@ Security
http://docs.ceph.com/docs/master/cephfs/file-layouts/
- An additional level of resource isolation can be provided by mapping a
- share's contents to a separate RADOS pool. This layout would be be preferred
+ share's contents to a separate RADOS pool. This layout would be preferred
only for cloud deployments with a limited number of shares needing strong
resource separation. You can do this by setting a share type specification,
``cephfs:data_isolated`` for the share type used by the cephfs driver.
