Error indexing vcf files containing "variants" in the file name

[j-coll]

The VariantReaderUtils is generating a wrong metadata file names for those files, replacing the first occurrence of "variants" instead of the last one:

NA00023_variants.vcf.gz                   -> original file
NA00023_variants.vcf.gz.variants.avro.gz  -> transformed file
NA00023_file.json.gz                      -> actual metadata file (wrong)
NA00023_variants.vcf.gz.file.json.gz      -> correct metadata file