* tools/dist/remove-trailing-whitespace.zsh: New script.

Patch by: hwright, me
(I adjusted the script found in the "remove trailing whitespace" commits' log
messages (r866391))


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1467189 13f79535-47bb-0310-9956-ffa450edef68