Stop the spam messages about svn perf updates and commits

Svn updates and commits have been broken for a while, but are on the list of
things to be fixed / converted to git. The messages are just spam now, and are
cluttering up mailboxes and the mailing list archives.
Merge pull request #234 from ronawho/turn-off-svn-failure-mails

Stop the spam messages about svn perf updates and commits

[ok'd on chat]

Svn updates and commits have been broken for a while, but are on the list of
things to be fixed / converted to git. The messages are just spam now, and are
cluttering up mailboxes and the mailing list archives.
Merged chapel-lang/master