Test Case Importer doesn't map the 'priority' field correctly

When importing from a CSV file where the priority field is an integer and not a string, the test case importer fails to map the priority level.

(example files can be found in the attachments)

 Steps to reproduce

Step	Result
Import tests through Test Case Importer, making sure that you map the values for the priority field.
Map the values of the field
Check the priority on the issues that were recently imported

If you use the String literal on the CSV, the test case importer works as expected, as long as the String matches the literal of the priority levels set for the project or the overall jira instance.