osd: fix small quirk read_log missing generation
osd: fix small quirk read_log missing generation

The missing entry .have field was probably wrong due to the use
of missing.add_event (which assumes missing is up to date wrt
the previous log entry).  Use the prior version we just pulled off
disk instead.

Also, be a bit more verbose.

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph