Files aren't renamed if the new filename only differs in casing from old filename

Description

This issue came up when we upgraded from swagger-codegen 2.2.3 to 2.3.1. This upgrade resulted in most of our generated files to be regenerated. However, there was a change in filename casing which wasn't picked up by swagger.

The old convention was: 'Test.ts' while the new one is 'test.ts'. After the regeneration was done, all files had updated contents but the file names weren't updated.

Current behaviour:
Filename Before upgrade: 'Test.ts'
Filename After upgrade: 'Test.ts'

Expected behaviour:
Filename Before upgrade: 'Test.ts'
Filename After upgrade: 'test.ts'

After removing all files and regeneration them again they generated with the proper file names.

Swagger-codegen version

2.3.1

Swagger declaration file content or url

N/A

Command line used for generation

swagger-codegen-maven-plugin

Steps to reproduce

1. Generate typescript-angular2 code with swagger-codegen-maven-plugin:2.2.3
2. Generate typescript-angular code with swagger-codegen-maven-plugin:2.3.1

Related issues/PRs

N/A

Suggest a fix/enhancement

N/A

OS

macOS High Sierra 10.13.6

Start at the swagger-codegen-maven-plugin entry point and reproduce generation first with typescript-angular2 on version 2.2.3, then typescript-angular on 2.3.1. The fix is complete when an existing Test.ts is renamed to test.ts during regeneration without deleting the generated files first.