revised ballgown

tasks/ballgown.wdl

@@ -6,7 +6,7 @@ task ballgown {
     String cluster
 
     command <<<
-      mkdir /cromwell_root/tmp/ballgown
+      mkdir -p /cromwell_root/tmp/ballgown
       cp -r ${sep=" " ballgown} /cromwell_root/tmp/ballgown
       Rscript /usr/bin/ballgown.R /cromwell_root/tmp/ballgown/${base} ${base}.txt
     >>>