Fix git URL in the release guide

git-svn-id: https://svn.apache.org/repos/asf/karaf/site/trunk@1551922 13f79535-47bb-0310-9956-ffa450edef68
Update the tools version in the release guide

git-svn-id: https://svn.apache.org/repos/asf/karaf/site/trunk@1551923 13f79535-47bb-0310-9956-ffa450edef68