tests: Add Testplan for testing reinstallation

Igor has recently gained some new features which now allow an automated
testing of updates.
This testplan requires this new features and allows the testing of
reinstallations.

Change-Id: Idf7dbcc93ddf4782e2313d4c42c96d67a8e073c6
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>