make mandatory variable checks only apply when needed

In our use case we might only be configuring mons and not osds in the
same call, so we don't want to check variables needed for osds when they
are not needed to configure a mon.

Signed-off-by: Andrew Schoen <aschoen@redhat.com>

roles/ceph-common/tasks/checks/check_mandatory_vars.yml

@@ -33,22 +33,30 @@
 - name: make sure journal_size configured
   fail:
     msg: "journal_size must be configured. See http://ceph.com/docs/master/rados/configuration/osd-config-ref/"
-  when: journal_size|int == 0
+  when:
+    journal_size|int == 0 and
+    osd_group_name in group_names
 
 - name: make sure monitor_interface configured
   fail:
     msg: "monitor_interface must be configured. Interface for the monitor to listen on"
-  when: monitor_interface == 'interface'
+  when:
+    monitor_interface == 'interface' and
+    mon_group_name in group_names
 
 - name: make sure cluster_network configured
   fail:
     msg: "cluster_network must be configured. Ceph replication network"
-  when: cluster_network == '0.0.0.0/0'
+  when:
+    cluster_network == '0.0.0.0/0' and
+    osd_group_name in group_names
 
 - name: make sure public_network configured
   fail:
     msg: "public_network must be configured. Ceph public network"
-  when: public_network == '0.0.0.0/0'
+  when:
+    public_network == '0.0.0.0/0' and
+    osd_group_name in group_names
 
 - name: make sure an osd scenario was chosen
   fail: