Fix up link to KEYS file

git-svn-id: https://svn.apache.org/repos/asf/creadur/rat/trunk@1513166 13f79535-47bb-0310-9956-ffa450edef68
Merge commit 'cc6ec88dced5d19bb449ae0b926d99f43b3eea99' into gsoc

# By Sebastian Bazley
# Via Sebastian Bazley
* commit 'cc6ec88dced5d19bb449ae0b926d99f43b3eea99':
  Fix up link to KEYS file