tests: fix a typo in dev_setup.yml

c907ec41ae introduced a typo.
This commit fixes it.

```
[WARNING]: While constructing a mapping from /home/guits/ceph-ansible/tests/functional/dev_setup.yml, line 21, column 9, found a duplicate dict key (replace).
```

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit 2798774e96)

tests/functional/dev_setup.yml

@@ -11,18 +11,20 @@
           set_fact:
             group_vars_path: "{{ change_dir + '/hosts' if 'ooo-collocation' in change_dir.split('/') else change_dir + '/group_vars/all' }}"
 
+        - block:
             - name: change ceph_repository to 'dev'
               replace:
                 regexp: "ceph_repository:.*"
                 replace: "ceph_repository: dev"
                 dest: "{{ group_vars_path }}"
-        when: change_dir is defined
 
-      - name: change nfs-ganesha repository to 'dev'
+            - name: ensure nfs_ganesha_stable is set to False
               replace:
                 regexp: "nfs_ganesha_stable=.*"
                 replace: "nfs_ganesha_stable=False"
                 dest: "{{ group_vars_path }}"
+
+            - name: ensure nfs_ganesha_dev is set to True
               replace:
                 regexp: "nfs_ganesha_dev:.*"
                 replace: "nfs_ganesha_dev=True"