FluentBit does not normalize log levels

The FluentBit conf has filters to normalize the log levels 

https://github.com/couchbase/couchbase-fluent-bit/blob/main/conf/couchbase/filter-handle-levels.conf#L9

Each [FILTER] has a condition 

Condition   Key_value_does_not_equal                        __temp_level_fixed Y 

But that variable is never default and none of the filters will apply.  When doing testing, I would get all of the various log levels and casings.  

The following filter needs to be the first one added in filter-handle-levels.conf

# Default the __temp_level_fixed variable to N

[FILTER]

    Name        modify

    Match       couchbase.log.*

    Alias       default_temp_level_fixed

    Set         __temp_level_fixed                              N 

Once the variable is default, all of the log levels are properly normalized.