fix bug

tasks/bcftools.wdl

 		set -e
 		mkdir -p /cromwell_root/tmp/bcftools
 
+		echo $vcf > b
 		for i in $vcf
 		do
 			bcftools view $i -Oz -o /cromwell_root/tmp/bcftools/$(basename $i.gz)
 
 		ls /cromwell_root/tmp/bcftools > a
 		cd /cromwell_root/tmp/bcftools
-		bcftools merge -m all -f PASS,. --force-samples *.gz | bcftools plugin fill-AN-AC | bcftools filter -i 'SUM(AC)>1' > panel_of_normal.vcf
+		bcftools merge -m all -f PASS,. --force-samples *.vcf.gz | bcftools plugin fill-AN-AC | bcftools filter -i 'SUM(AC)>1' > panel_of_normal.vcf
 	>>>
 
 	runtime {
 	output {
 		File panel_of_normal_vcf = "panel_of_normal.vcf"
 		File a = "a"
+		File b = "b"
 	}
 }