s3:dbwrap_ctdb: fix logic error in pull_newest_from_marshall_buffer().
The logic bug was that if a record was found in the marshall buffer,
then always the ctdb header of tha last record in the marshall buffer
was returned, and not the ctdb header of the last occurrence of the
requested record.
This is fixed by introducing an additional temporary variable.
Michael
(cherry picked from commit
524072b56bf659002410a817749bf86fe6f51e83)
(cherry picked from commit
e5cc0e718863d6cfaa59fbb4cac7d9b70fba0381)