Add three new CLI tests of sahara

This patch adds test cases for sahara CLI Positional arguments:
1. bash-completion
2. help

This patch adds test cases for sahara CLI Optional arguments:
1. version

Partially implements: blueprint cli-tests-coverage

Change-Id: I59c7dd34cdb625eba370aa2a02c7cd25f713fcc0
Merge "Add three new CLI tests of sahara"