BWA-MEM corrupted indexes

These seem to be CVMFS

Identified so far

* `dm3`
* [testing history](https://usegalaxy.eu/u/jenj/h/galaxy-workflow-galaxy-hi-c-1) using the [hic workflow in this tutorial](https://training.galaxyproject.org/training-material/topics/epigenetics/tutorials/hicexplorer/tutorial.html). This is the [Ghelp topic](https://help.galaxyproject.org/t/convert-galaxy-output-hic-file-to-hic-file-for-use-on-ucsc-genome-browser/12833/4)
```
Traceback (most recent call last):
File "/opt/galaxy/shed_tools/toolshed.g2.bx.psu.edu/repos/crs4/bwa_mem/ebb02ba5987c/bwa_mem/bwa_mem.py", line 234, in __main__
raise Exception( 'Error generating alignments. ' + str( e ) )
Exception: Error generating alignments. can only concatenate str (not "bytes") to str
```

Human
* `hg38female`
* `hg19canon`
* [testing history](https://usegalaxy.org/u/jen-galaxyproject/h/test-bwa-mem-human-hg19-hg38-indexes) and [ghelp topic ](https://help.galaxyproject.org/t/map-with-bwa-mem-not-working-with-one-particular-reference-genome/13258/5)
```
[E::bwa_idx_load_from_disk] fail to locate the index files
[W::hts_set_opt] Cannot change block size for this format
samtools sort: failed to read header from "-"
```

Reported at https://help.galaxyproject.org/t/map-with-bwa-mem-not-working-with-one-particular-reference-genome/13258/6

Related to this? https://help.galaxyproject.org/t/genomes-are-missing-from-the-dbdey-table-while-present-in-bowtie2/11972/4?u=jennaj

Start with the BWA-MEM reference indexes listed for dm3, hg38female, and hg19canon, and inspect the bwa_mem.py failure at line 234 alongside the reported CVMFS paths. Reproduce the failures using the linked testing histories and confirm that the affected indexes load and complete alignment without the shown errors.

Written by the indexing model from the issue text.