Change mpivars.sh to work if no mpi is present

Author: arnaudfroidmont

playbooks/roles/mpivars/tasks/ubuntu.yml

@@ -11,7 +11,7 @@
   stat:
     path: /usr/mpi/gcc/{{ openmpi.stdout_lines[0] }}/bin/mpivars.sh
   register: mpivars
-  when: openmpi.stdout_lines[0] != ""
+  when: openmpi.stdout_lines | length > 0
 
 
 - name: Create mpivars.sh
@@ -22,4 +22,4 @@
     force: yes
     owner: root
     group: root
-  when: openmpi.stdout_lines[0] != "" and not mpivars.stat.exists
+  when: openmpi.stdout_lines | length > 0 and not mpivars.stat.exists