fixed file-source

Changing file source info to contain vds info. We made some changes for file source infos for segy-to-vds-conversion#15 (closed).

The resultant Dataset looks like this for now, without these changes:

"DatasetProperties": {
            "FileCollectionPath": "sd://opendes/autotest/test_vds_id_999947655129",
            "FileSourceInfos": "[[{'FileSource': 'sd://opendes/autotest/ST10010ZC11_PZ_PSDM_KIRCH_FULL_T.MIG_FIN.POST_STACK.3D.JS-017536.segy', 'PreloadFilePath': '', 'Name': 'OSDU_SEGY'}]]"
        }

Not a properly formatted json, plus the file source should be telling about the vds file and not the segy file. So, until segy-to-vds-conversion#17 gets implemented, this is a temp fix. With this, now we get:

"FileCollectionPath": "sd://opendes/autotest/test_vds_id_999750650895",
            "FileSourceInfos": [
                {
                    "FileSource": "sd://opendes/autotest/test_vds_id_999750650895"
                }
            ]