[GH-91] default file stage in strategy to copy

As title.  If scratch is not specified, default to true and set the
stage in strategy to copy to avoid symbolic link between local
filesystem and s3fs.

plugins/nf-float/src/main/com/memverge/nextflow/FloatGridExecutor.groovy

@@ -103,14 +103,14 @@ class FloatGridExecutor extends AbstractGridExecutor {
 
     protected BashWrapperBuilder createBashWrapperBuilder(TaskRun task) {
         final bean = new TaskBean(task)
+        if (bean.scratch == null) {
+            // default scratch to true
+            bean.scratch = true
+            bean.stageInMode = 'copy'
+        }
         final strategy = new FloatFileCopyStrategy(floatConf, bean)
         // creates the wrapper script
         final builder = new BashWrapperBuilder(bean, strategy)
-        if (builder.scratch == null) {
-            // default scratch to true
-            builder.scratch = true
-            builder.stageInMode = 'copy'
-        }
         // job directives headers
         builder.headerScript = getHeaderScript(task)
         return builder