crimson/osd: don't capture a local, on-stack address of MOSDRepOpReply

crimson/osd: don't capture a local, on-stack address of MOSDRepOpReply

This flaw can explain the following crash observed at Sepia:

```
ceph-osd: /home/jenkins-build/build/workspace/ceph-dev-new-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos8/DIST/centos8/MACHINE_SIZE/gigantic/release/17.0.0-13661-g3a14f283/rpm/el8/BUILD/ceph-17.0.0-13661-g3a14f283/x86_64-redhat-linux-gnu/boost/include/boost/smart_ptr/intrusive_ptr.hpp:199: T* boost::intrusive_ptr<T>::operator->() const [with T = MOSDRepOpReply]: Assertion `px != 0' failed.
Aborting on shard 0.
Backtrace:
 0# gsignal in /lib64/libc.so.6
 1# abort in /lib64/libc.so.6
 2# 0x00007FB1346F4CD9 in /lib64/libc.so.6
 3# 0x00007FB13471A3F6 in /lib64/libc.so.6
 4# crimson::osd::OSD::handle_rep_op_reply(seastar::shared_ptr<crimson::net::Connection>, boost::intrusive_ptr<MOSDRepOpReply>) in ceph-osd
 5# 0x000055C4100FF8D0 in ceph-osd
 6# 0x000055C410100639 in ceph-osd
 7# crimson::osd::OSD::ms_dispatch(seastar::shared_ptr<crimson::net::Connection>, boost::intrusive_ptr<Message>) in ceph-osd
 8# crimson::net::ChainedDispatchers::ms_dispatch(seastar::shared_ptr<crimson::net::Connection>, boost::intrusive_ptr<Message>) in ceph-osd
 9# 0x000055C4165220EF in ceph-osd
10# 0x000055C416532791 in ceph-osd
11# 0x000055C4165328B2 in ceph-osd
12# 0x000055C40FDD33D5 in ceph-osd
13# 0x000055C40FDEE2CE in ceph-osd
14# 0x000055C40FDEEEF0 in ceph-osd
15# 0x000055C41CA41215 in ceph-osd
16# 0x000055C41CA97959 in ceph-osd
17# 0x000055C41CBF73A0 in ceph-osd
18# 0x000055C41CBF93F5 in ceph-osd
19# 0x000055C41C629A46 in ceph-osd
20# 0x000055C41C62E012 in ceph-osd
21# main in ceph-osd
22# __libc_start_main in /lib64/libc.so.6
23# _start in ceph-osd
```

Signed-off-by: Radoslaw Zarzynski <rzarzyns@redhat.com>