Added missing Tag class to fix display of tags on Infra Topology.

[h-kataria]

Fixed a Label on the screen

https://bugzilla.redhat.com/show_bug.cgi?id=1454295

before

after

[miq-bot]

Checked commit h-kataria@fd5fa53 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
2 files checked, 0 offenses detected
Everything looks fine. 🍰

[simaishi]

Fine backport details:

$ git log -1
commit 15149d076b6de975c0b9372d3bea87708f737d3f
Author: Milan Zázrivec <mzazrivec@redhat.com>
Date:   Wed May 24 10:57:06 2017 +0200

    Merge pull request #1404 from h-kataria/show_tags_on_infra_topology
    
    Added missing Tag class to fix display of tags on Infra Topology.
    (cherry picked from commit 6482ca38afdb022c3e565dfb070cde3595e64e97)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1460036

[simaishi]

@h-kataria please address Travis failure (https://travis-ci.org/ManageIQ/manageiq-ui-classic/jobs/240982977) in Fine branch:

  1) InfraTopologyService#build_kinds creates the expected number of entity types
     Failure/Error:
       expect(infra_topology_service.build_kinds.keys).to match_array(
         [:InfraManager, :EmsCluster, :Host, :Vm])
     
       expected collection contained:  [:EmsCluster, :Host, :InfraManager, :Vm]
       actual collection contained:    [:EmsCluster, :Host, :InfraManager, :Tag, :Vm]
       the extra elements were:        [:Tag]