GlusterFS: Don't use /dev/null for empty file.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1478198

Signed-off-by: Jose A. Rivera <jarrpa@redhat.com>

roles/openshift_storage_glusterfs/README.md

@@ -97,7 +97,7 @@ GlusterFS cluster into a new or existing OpenShift cluster:
 | openshift_storage_glusterfs_heketi_ssh_port      | 22                      | SSH port for external GlusterFS nodes via native heketi
 | openshift_storage_glusterfs_heketi_ssh_user      | 'root'                  | SSH user for external GlusterFS nodes via native heketi
 | openshift_storage_glusterfs_heketi_ssh_sudo      | False                   | Whether to sudo (if non-root user) for SSH to external GlusterFS nodes via native heketi
-| openshift_storage_glusterfs_heketi_ssh_keyfile   | '/dev/null'             | Path to a private key file for use with SSH connections to external GlusterFS nodes via native heketi **NOTE:** This must be an absolute path
+| openshift_storage_glusterfs_heketi_ssh_keyfile   | Undefined               | Path to a private key file for use with SSH connections to external GlusterFS nodes via native heketi **NOTE:** This must be an absolute path
 | openshift_storage_glusterfs_heketi_wipe          | False                   | Destroy any existing heketi resources, defaults to the value of `openshift_storage_glusterfs_wipe`
 
 Each role variable also has a corresponding variable to optionally configure a

roles/openshift_storage_glusterfs/defaults/main.yml

@@ -23,7 +23,7 @@ openshift_storage_glusterfs_heketi_executor: 'kubernetes'
 openshift_storage_glusterfs_heketi_ssh_port: 22
 openshift_storage_glusterfs_heketi_ssh_user: 'root'
 openshift_storage_glusterfs_heketi_ssh_sudo: False
-openshift_storage_glusterfs_heketi_ssh_keyfile: '/dev/null'
+openshift_storage_glusterfs_heketi_ssh_keyfile: "{{ omit }}"
 openshift_storage_glusterfs_namespace: "{{ 'glusterfs' | quote if openshift_storage_glusterfs_is_native or openshift_storage_glusterfs_heketi_is_native else 'default' | quote }}"
 
 openshift_storage_glusterfs_registry_timeout: "{{ openshift_storage_glusterfs_timeout }}"
@@ -51,4 +51,4 @@ openshift_storage_glusterfs_registry_heketi_executor: "{{ openshift_storage_glus
 openshift_storage_glusterfs_registry_heketi_ssh_port: "{{ openshift_storage_glusterfs_heketi_ssh_port }}"
 openshift_storage_glusterfs_registry_heketi_ssh_user: "{{ openshift_storage_glusterfs_heketi_ssh_user }}"
 openshift_storage_glusterfs_registry_heketi_ssh_sudo: "{{ openshift_storage_glusterfs_heketi_ssh_sudo }}"
-openshift_storage_glusterfs_registry_heketi_ssh_keyfile: "{{ openshift_storage_glusterfs_heketi_ssh_keyfile }}"
+openshift_storage_glusterfs_registry_heketi_ssh_keyfile: "{{ openshift_storage_glusterfs_heketi_ssh_keyfile | default(omit) }}"

roles/openshift_storage_glusterfs/tasks/glusterfs_common.yml

@@ -165,7 +165,8 @@
 
 - name: Copy heketi private key
   copy:
-    src: "{{ glusterfs_heketi_ssh_keyfile }}"
+    src: "{{ glusterfs_heketi_ssh_keyfile | default(omit)  }}"
+    content: "{{ '' if glusterfs_heketi_ssh_keyfile is undefined else omit }}"
     dest: "{{ mktemp.stdout }}/private_key"
 
 - name: Create heketi config secret