Set identifier on log entries before attempting to get the DSpace object

Some null identifiers in the logs were due to GETs on objects that didn't exist.
NotFoundException was thrown before the log entry was populated with the requested identifier
Also make sure log entry identifier is set early in getReplica
Add shouldRecord to LogEntry

Value is initially true, set to false if object is not found, and checked by DataOneMN before logging
Merge pull request #244 from datadryad/trello-9-dataonemn-6

Prevent DataOne MN log entries from having null identifiers