Miscellaneous documentation bugs in VNF scaling guide

[Manpreet Kaur]

This bug tracker is for errors with the documentation, use the following as a template and remove or add fields as you see fit. Convert [ ] into [x] to check boxes:

- [x ] This doc is inaccurate in this way:
  Few miscellaneous documentation bugs are identified in VNF scaling guide,
  * Missing articulation in the document.
  * Old link present for Tacker TOSCA template.
  * Mix convention used in the guide for word "Tacker".
- [ ] This is a doc addition request.
- [ ] I have a fix to the document that I can paste below including example: input and output.

If you have a troubleshooting or support issue, use the following resources:

 - The mailing list: https://lists.openstack.org
 - IRC: 'openstack' channel on Freenode

-----------------------------------
Release: 4.1.0.dev87 on 2018-06-26 12:31:19
SHA: ae376f377ea85cb68234ecd0a61bf6728052c982
Source: https://opendev.org/openstack/tacker/src/doc/source/user/scale_usage_guide.rst
URL: https://docs.openstack.org/tacker/latest/user/scale_usage_guide.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/762947

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tacker 5.0.0.0rc1 release candidate.