fs-integration: Remove already grouped duplicate variants

With [1] all possible share configurations are grouped after their
respective backend file system. So those duplicate entries can be
removed reducing the number of jobs in the matrix.

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

jobs/fs-integration.yml

@@ -7,10 +7,8 @@
       - 'glusterfs'
       - 'xfs'
       - 'cephfs'
-      - 'cephfs.vfs'
       - 'cephfs.mgr.vfs'
       - 'gpfs'
-      - 'gpfs.vfs'
       - 'gpfs.scale'
     jobs:
       - 'samba_{file_system}-integration-{git_repo}'