mds,rgw: Initializing standby_reply, sync_tracer

mds,rgw: Initializing standby_reply, sync_tracer

Fixes te coveity issue:

** 1396192 Uninitialized scalar field
CID 1396192 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
2. uninit_member: Non-static class member standby_replay is
not initialized in this constructor nor in any functions that it calls.

** 717382 Uninitialized pointer field
CID 717382 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
2. uninit_member: Non-static class member sync_tracer is not
initialized in this constructor nor in any functions that it calls.

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