filesystem tests: update ocfs2 fs size on Trusty

Using Ubuntu 14.04, test fails because 'blkid' < 2.21 doesn't recognize
'ocfs2' filesystem smaller than 108Mo:
6baa150398

filesystem: fix MKFS_FORCE_FLAGS for ocfs2

mkfs.ocfs2 -F won't work because mkfs.ocfs2 asks for a confirmation:

    $ mkfs.ocfs2 -F img
    mkfs.ocfs2 1.6.4
    Cluster stack: classic o2cb
    Overwriting existing ocfs2 partition.
    WARNING: Cluster check disabled.
    Proceed (y/N):

The undocumented 'x' switch must be used too.

lib/ansible/modules/system/filesystem.py

@@ -230,6 +230,7 @@ class Btrfs(Filesystem):
 
 class Ocfs2(Filesystem):
     MKFS = 'mkfs.ocfs2'
+    MKFS_FORCE_FLAGS = '-Fx'
 
 
 class VFAT(Filesystem):

test/integration/targets/filesystem/defaults/main.yml

@@ -12,5 +12,5 @@ tested_filesystems:
   xfs: {fssize: 20, grow: False}  # grow requires a mounted filesystem
   btrfs: {fssize: 100, grow: False}  # grow not implemented
   vfat: {fssize: 20, grow: True}
-  ocfs2: {fssize: 20, grow: False}  # grow not implemented
+  ocfs2: {fssize: '{{ ocfs2_fssize }}', grow: False}  # grow not implemented
   # untested: lvm, requires a block device

test/integration/targets/filesystem/tasks/main.yml

@@ -4,6 +4,15 @@
     msg: '{{ role_path|basename }}'
 - import_tasks: setup.yml
 
+- include_vars: "{{ lookup('first_found', search) }}"
+  vars:
+    search:
+      files:
+        - '{{ ansible_distribution }}-{{ ansible_distribution_version }}.yml'
+        - 'default.yml'
+      paths:
+        - '../vars/'
+
 - include_tasks: create_fs.yml
   vars:
     dev: '{{ ansible_user_dir }}/ansible_testing/img'

test/integration/targets/filesystem/vars/Ubuntu-14.04.yml

@@ -0,0 +1,2 @@
+---
+ocfs2_fssize: 108

test/integration/targets/filesystem/vars/default.yml

@@ -0,0 +1,2 @@
+---
+ocfs2_fssize: 20