Description of problem:
ceph-ansible should require python-netaddr, since it uses Ansible's ipaddr filter

Version-Release number of selected component (if applicable):
3.0

How reproducible:
Fully reproducible

Steps to Reproduce:
1. Install ceph-ansible
2. Set monitor_address_block
3. Run ceph-ansible

Actual results:
TASK [ceph-config : generate ceph configuration file: ceph.conf] *************************************
   fatal: [c05-h33-6018r]: FAILED! => {"msg": "The ipaddr filter requires python-netaddr be installed on the ansible controller"}

Expected results:
ceph-ansible completes successfully

Additional info:

python-netaddr should be made a dependency for ceph-ansible.