DAOS-19132 rdb: Fix destination ranks in log messages (#18481)

[liw]

Rajesh observed log messages like these:

crt_rpc_complete_and_unlock(0x7efc3df4a620) [opc=0x7040000
  (DAOS_RDB_MODULE:) rpcid=0x3637ab4c00003653 rank:tag=102:0]
  failed, DER_OOG(-1019): 'Out of group or member list'
rdb_raft_rpc_cb() 14673705[207]: RPC 0 to rank 0 failed:
  DER_OOG(-1019): 'Out of group or member list'

Apparently, rdb_raft_rpc_cb should log 'to rank 102' instead of 'to rank 0'. The issue is that depending on when the error happens the destination rank in the request header may have yet to be initialized. This patch returns to use cr_ep.ep_rank for request senders.

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'Aurora daos_user: Destination ranks in rdb_raft_rpc_cb log messages may be incorrect'
Status is 'Awaiting backport'
Labels: 'ALCF'
Job should run at elevated priority (1)
https://daosio.atlassian.net/browse/DAOS-19132