Blobtoolkit can have trouble parsing raw Diamond results

[jennaj]

https://github.com/bgruening/galaxytools/blob/211f182d517e5416ed24f9cc404b717eb7f6471a/tools/blobtoolkit/blobtoolkit.xml#L199

If the Diamond hit input has an empty 7th column (possible!) the Blobtoolkit tool can fail. See https://help.galaxyproject.org/t/problem-on-following-the-post-assembly-qc-workflow/12967