Minor fix for the aws_start script.

Change-Id: I7446868484a1ffd7ca84c3652276e69db5208498
Reviewed-on: https://asterix-gerrit.ics.uci.edu/1599
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
BAD: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Ian Maxon <imaxon@apache.org>
diff --git a/asterixdb/asterix-server/src/main/opt/aws/yaml/aws_start.yml b/asterixdb/asterix-server/src/main/opt/aws/yaml/aws_start.yml
index 5287e34..344bfd5 100644
--- a/asterixdb/asterix-server/src/main/opt/aws/yaml/aws_start.yml
+++ b/asterixdb/asterix-server/src/main/opt/aws/yaml/aws_start.yml
@@ -29,8 +29,10 @@
   tasks:
     - include_vars: ../conf/aws_settings.yml
     - include_vars: ../conf/aws_types.yml
-    - debug:
-        msg: "{{ vols }}"
+
+    - name: Clean the temporary directory
+      shell: rm -rf "{{ temp_dir }}"
+
     - name: Launch all instances
       ec2:
         key_name: "{{ keypair }}"
@@ -110,7 +112,7 @@
 
     - name: Populate multiple iodevices
       shell: printf "  - /data{{ vol.0 + 1 }}/iodevice\n" >> "{{ temp_dir }}/devices"
-      with_indexed_items: vols
+      with_indexed_items: "{{ vols }}"
       loop_control:
         loop_var: vol
       when: vols|length > 0