IPv6 test cases: Test case specification document example

IPv6 test cases: Test case specification document example

JIRA: DOVETAIL-9

1. We are keeping the test methodology simple and easy.
   We are reusing existing tests as much as we can from
   IPv6 projects and Tempest API and Scenario tests, which
   are run in FuncTest and Yardstick.

2. We modified "testplan.rst" to briefly describe the test plan,
   i.e. current IPv6 test cases for platform compliance, which
   have passed FuncTest and Yardstick test in Arno and Brahmaputra
   releases. We also leave room for additional IPv6 test cases if
   there are more contributions down the road

3. Original "designspecification.rst", "testprocedure.rst" and
   "testspecification.rst" are not applicable any more here. The
   test design, setup, and execution procedure related specification
   are covered by each test case.

4. Thus "index.rst" only covers "testplan.rst" and the list of test cases.

5. Two examples of test case specification documents are provided
   "ipv6.tc001.specification.rst"
   "ipv6.tc026.specification.rst"

6. A complete set of current IPv6 test cases are listed in
   "ipv6_all_testcases.rst". Once template is agreed, we will converted
   it into specific test case document.

For more background of IPv6, and its features and technical details, please see:
   https://wiki.opnfv.org/display/ipv6/IPv6+Home
   http://artifacts.opnfv.org/ipv6/docs/installationprocedure/index.html

Change-Id: I7e47c73c0f02a407df278c93a3da2142b5cc86e5
Signed-off-by: Bin Hu <bh526r@att.com>