Ensure log entries in the metadata table are up-to-date on upgrade (or remove strict validation)

[ctubbsii]

#3997 added stricter validation when reading log entries in the metadata. It now verifies that it sees the - as a placeholder for a field that used to be present, but now is no longer used. However, if a system is upgraded to 2.1, then subsequently upgraded to 3.1 while it still contains log entries in the metadata tables, then this validation will fail.

One of the following tasks should be done prior to release:

1. Remove strict validation (not care if the unused first field is a - or not), or
2. Add upgrade code to rewrite all log entries in the metadata table to replace the field with a - (and can also remove the Value, which is no longer used as well)