fix some use of conditional variables

roles/slurm-from-source/tasks/main.yml

@@ -120,7 +120,7 @@
 - name: install gres config file 
   template: src=gres.conf.j2 dest={{ slurm_dir }}/etc/gres.conf mode=644
   sudo: true
-  when: slurm_generic_resource.stdout 
+  when: slurm_generic_resource is defined and slurm_generic_resource.stdout 
 
 - name: install gres sub config file 
   template: src=gres_sub.conf.j2 dest={{ slurm_dir }}/etc/gres/gres.conf mode=644
@@ -131,7 +131,7 @@
   template: src=slurm.conf.j2 dest={{ slurm_dir }}/etc/slurm.conf
   sudo: true
   notify: restart slurm
-  when: slurm_use_vpn==False and slurm_gres_list is defined
+  when: slurm_use_vpn==False 
 
 - name: install slurm.conf
   template: src=slurm-vpn.conf.j2 dest={{ slurm_dir }}/etc/slurm.conf