fs-integration: Use the new name for mgr variant of cephfs

With [1] suffix 'vfs' is irrelevant in 'cephfs.mgr.vfs' as multiple
share configurations are included within mgr variant.

[1] samba-in-kubernetes/sit-environment#117

jobs/fs-integration.yml

@@ -7,7 +7,7 @@
       - 'glusterfs'
       - 'xfs'
       - 'cephfs'
-      - 'cephfs.mgr.vfs'
+      - 'cephfs.mgr'
       - 'gpfs'
       - 'gpfs.scale'
     jobs: