Fix if not exist in bdbagFetch.sh

workflow/scripts/bdbagFetch.sh

 #!/bin/bash
 
-if [ ! -z ${3}} ]
+if [ -z ${3}} ]
 then
 bdbag --resolve-fetch all --fetch-filter filename\$*fastq.gz ${1}
     for i in $(find */ -name "*.R*.fastq.gz")