fix(config): correct LOG_HANDLER and LOGFILE variable assignments in template-odoo-rc

* Fix incorrect assignment of `LOG_HANDLER` and `LOGFILE` which were mistakenly using `LIST_DB`'s value
* Ensure each environment variable is assigned its intended default value
* Align with existing pattern of self-referential default assignments for consistency

images/odoo/bin/template-odoo-rc

@@ -15,7 +15,7 @@ export LOG_LEVEL=${LOG_LEVEL:="info"}
 export MAX_CRON_THREADS=${MAX_CRON_THREADS:=2}
 export LIST_DB=${LIST_DB:=False}
 export LOG_DB=${LOG_DB:=False}
-export LOG_HANDLER=${LIST_DB:="[':INFO']"}
+export LOG_HANDLER=${LOG_HANDLER:="[':INFO']"}
 export LOGFILE=${LIST_DB:="None"}
 export ADMIN_PASSWD=${ADMIN_PASSWD:="odoo"}
 export DB_FILTER=${DB_FILTER:=""}