crimson/osd: fix stuck recovery

crimson/osd: fix stuck recovery

https://github.com/ceph/ceph/pull/62080 tested version was **different**
from the one that got merged.
The untested change was changing the boolean returned from start_recovery_ops.
While the seastar::repeat loop in BackgroundRecoveryT<T>::start() was changed accordingly,
other do_recovery() return cases were not considered.

See Tested / Merged here: https://github.com/Matan-B/ceph/pull/2/files

start_recovery_ops used by do_recovery should return whether the iteration (i.e recovery) keep going.

_Note: This has caused a regression in our suite_

Signed-off-by: Matan Breizman <mbreizma@redhat.com>