tooling/release: add .gitignore

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1630400 13f79535-47bb-0310-9956-ffa450edef68
SLING-3586 - Publishing content fails if intermediate nodes are not
present in the repository

Ensure that when a resource is published all its parents, up to the
repository root, are created.

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1630401 13f79535-47bb-0310-9956-ffa450edef68