fix decoding bug in dna kmer

run1

seb@bigmem:~/biosal$ sha1sum coverage_distribution.txt
5d59ce23557c390379f9a1372d149a07bdb68d68  coverage_distribution.txt

seb@bigmem:~/biosal$ grep local log |awk '{print $6}'|sort -n |sha1sum
3c6977e855f5ca294cc5cff5825fa49250a54229 -

run2

seb@bigmem:~/biosal$ sha1sum coverage_distribution.txt
5d59ce23557c390379f9a1372d149a07bdb68d68  coverage_distribution.txt

seb@bigmem:~/biosal$ grep local log |awk '{print $6}'|sort -n |sha1sum
3c6977e855f5ca294cc5cff5825fa49250a54229  -

Link: https://github.com/GeneAssembly/biosal/issues/241
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>