Prevent NPE with null AWS Batch response

Signed-off-by: Paolo Di Tommaso <[email protected]>

plugins/nf-amazon/src/main/nextflow/cloud/aws/batch/AwsBatchTaskHandler.groovy

@@ -198,7 +198,7 @@ class AwsBatchTaskHandler extends TaskHandler implements BatchHandler<String,Job
         // retrieve the status for the specified job and along with the next batch
         log.trace "[AWS BATCH] requesting describe jobs=${jobIdsToString(batchIds)}"
         DescribeJobsResult resp = client.describeJobs(new DescribeJobsRequest().withJobs(batchIds))
-        if( !resp.getJobs() ) {
+        if( !resp || !resp.getJobs() ) {
             log.debug "[AWS BATCH] cannot retrieve running status for job=$jobId"
             return null
         }