increase code coverage to 80%

[steenzout]

------------------------------------------- generated xml file: /Users/steenzout/Projects/github/dellis23/ansible-toolkit/tests/junit.xml -------------------------------------------
----------------------------------------------------------------- coverage: platform darwin, python 2.7.11-final-0 ------------------------------------------------------------------
Name                                     Stmts   Miss  Cover   Missing
----------------------------------------------------------------------
ansible_toolkit/__init__.py                  0      0   100%   
ansible_toolkit/exceptions.py                2      0   100%   
ansible_toolkit/git_diff.py                 73     17    77%   51, 74-75, 131-144, 148-150
ansible_toolkit/show_template.py            10     10     0%   1-20
ansible_toolkit/show_vars.py                34     34     0%   1-71
ansible_toolkit/tests/git_diff_test.py      70      1    99%   161
ansible_toolkit/utils.py                    61     36    41%   25, 29, 33, 37, 41, 48-51, 58-65, 71-77, 88-94, 102-111
ansible_toolkit/utils_ansible.py            26     26     0%   1-58
ansible_toolkit/vault.py                    44     44     0%   1-91
----------------------------------------------------------------------
TOTAL                                      320    168    48%