Worklog clause should not be case sensitive

We've got three worklog related clauses available for the JQL:

• worklogDate
• worklogAuthor
• worklogratio

If we use the clause "worklogdate" or "worklogauthor" instead of "worklogDate" or "worklogAuthor" , JIRA consider that is not using the default worklog clause and skip the query optimisation feature when constructing the lucene search query. The consequence makes that JIRA took a longer time to return the search result.