specs: require of e2fsprogs

specs: require of e2fsprogs

in ceph/ceph-container we've realized that `e2fsprogs` isn't installed in
centos container image because ceph hasn't a dependency for it.
It has for consequence to fail when deploying a containerized cluster
with dmcrypt when using centos image.

Typical error encountered:

typical error:
```
......
get_dm_uuid: get_dm_uuid /dev/sda uuid path is /sys/dev/block/8:0/dm/uuid
get_dm_uuid: get_dm_uuid /dev/sda uuid path is /sys/dev/block/8:0/dm/uuid
get_dm_uuid: get_dm_uuid /dev/sda5 uuid path is /sys/dev/block/8:5/dm/uuid
populate: Creating lockbox fs on %s: mkfs -t ext4 /dev/sda5
command_check_call: Running command: /usr/sbin/mkfs -t ext4 /dev/sda5
mkfs.ext4: No such file or directory
Traceback (most recent call last):
  File "/usr/sbin/ceph-disk", line 9, in <module>
    load_entry_point('ceph-disk==1.0.0', 'console_scripts', 'ceph-disk')()
......
```

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>