Client: get describe_layout by file handle/path

Signed-off-by: Andras Elso <elso.andras@gmail.com>
libcephfs: fix typos

Signed-off-by: Andras Elso <elso.andras@gmail.com>
libcephfs: get stripe_unit/stripe_count/object_size/pool_id by file handle/path

Signed-off-by: Andras Elso <elso.andras@gmail.com>
libcephfs: get file handle/path layout info

Signed-off-by: Andras Elso <elso.andras@gmail.com>
libcephfs: get replication factor of a file handle/path

Signed-off-by: Andras Elso <elso.andras@gmail.com>