Improve the security group rules output when running the
"os security group show" command. Empty and duplicate
information for each security group rule is now removed.
This will ensure that the rules remain readable when
direction and ethertype information is returned as part
of the transition to neutron networking.
Change-Id: Ib49c27a9d7f4d5d38ceb2b0d785ddf94d88b2d89
Partial-Bug: #1519511
Related-To: blueprint neutron-client