Problem with local storage entries form elder versions

[martinroob]

When starting tiny-translator with there is this error:
app.component.html:3 ERROR TypeError: Cannot read property 'accessorType' of null at SerializationService.push../src/app/model/serialization.service.ts.SerializationService.deserializeIFileConfiguration (serialization.service.ts:59) at Function.push../src/app/file-accessors/download-upload/download-upload-file-description.ts.DownloadUploadFileDescription.deserialize (download-upload-file-description.ts:22) at Function.push../src/app/model/translation-file.ts.TranslationFile.fromDeserializedObject (translation-file.ts:124) at Function.push../src/app/model/translation-file.ts.TranslationFile.deserialize (translation-file.ts:110) at Function.push../src/app/model/translation-project.ts.TranslationProject.deserialize (translation-project.ts:56) at backend-local-storage.service.ts:48 at Array.map (<anonymous>) at BackendLocalStorageService.push../src/app/model/backend-local-storage.service.ts.BackendLocalStorageService.projects (backend-local-storage.service.ts:48) at new TinyTranslatorService (tiny-translator.service.ts:35) at _createClass (core.js:21267)
We should fix the code that it can run with elder entries in the local storage.