Fix librados:;IoCtxImpl::write_full () to return bytes written
Proposed fix for 7952.  Have return_value() of a aio_read return the bytes read

Signed-off-by: David Zafman <david.zafman@inktank.com>
Improve ceph_scratchtoolpp

Minor output improvements
Disable clone_range code that was asserting
Disable snap section because snap_add crashes ceph-osd in old_snapshot_add()

Signed-off-by: David Zafman <david.zafman@inktank.com>
librados: Allow rados_pool_list() to get NULL buffer if len == 0

Coverity wants a NULL check for buf, but caller should be able to
pass a NULL buf and 0 len in order to get byte count of pool list.

Signed-off-by: David Zafman <david.zafman@inktank.com>
librados, test: Make return values consistent across reads and writes

Fix consistency of read, write, append, write_full to return bytes read/written
Include C (rados_*) variants, C++ ctx variants
and aio get_return_value() and rados_aio_get_return_value()

Signed-off-by: David Zafman <david.zafman@inktank.com>