Merge branch '2018Dec04' into 'master'

Ignore error with the installation of development tools

See merge request hpc-team/ansible_cluster_in_a_box!219

roles/gpu/tasks/main.yml

@@ -29,6 +29,7 @@
   yum: name="@Development Tools" state=installed
   become: true
   become_user: root
+  ignore_errors: yes
 
 - name: disable nouveau
   template: src=blacklist-nouveau.conf.j2 dest=/etc/modprobe.d/blacklist-nouveau.conf