Configuration for Maven version 3.2.2
Allow to overwrite shasum for unknown maven version
Add assertion on usable version variables
One-step assertion for version vars
Merge pull request #6 in ISAR/ansible-maven from ~KUSCH/ansible-maven:hotfix/default-version-shasum to next

* commit '44bc60c95a4e2fff846ed58e29954a11a7fa34ea':
  One-step assertion for version vars
  Add assertion on usable version variables
  Allow to overwrite shasum for unknown maven version
ansible-maven 0.5.1: Allow to overwrite shasum for unknown maven version