messages: Initializing members in MOSDPGUpdateLogMissing

messages: Initializing members in MOSDPGUpdateLogMissing

Fixes the coverity issues:

** 1355242 Uninitialized scalar field
2. uninit_member: Non-static class member map_epoch is not initialized
in this constructor nor in any functions that it calls.
4. uninit_member: Non-static class member min_epoch is not initialized
in this constructor nor in any functions that it calls.
CID 1355242 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
6. uninit_member: Non-static class member rep_tid is not initialized
in this constructor nor in any functions that it calls.

** 1355243 Uninitialized scalar field
2. uninit_member: Non-static class member map_epoch is not initialized
in this constructor nor in any functions that it calls.
4. uninit_member: Non-static class member min_epoch is not initialized
in this constructor nor in any functions that it calls.
CID 1355243 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
6. uninit_member: Non-static class member rep_tid is not initialized
in this constructor nor in any functions that it calls.

Signed-off-by: Amit Kumar amitkuma@redhat.com