Since I'm no longer with 18F, I've re-released hmacauth under the ISC
license as opposed to the previous CC0 license. There have been no
changes to the hmacauth code itself, and all tests still pass.
On these platforms, the `done <- true` statement in during TearDown() was
hanging, since the `watcher_unsupported.go` version was never draining the
channel. Also took the opportunity to update the WatchForUpdates() signature
to not return bool anymore.
TestValidatorOverwriteEmailListViaRenameAndReplace was deadlocking on
Windows because, on Windows, fsnotify.Watcher will continue to watch a
renamed file using its new name. On other systems, it appears the watch on
a file is removed after a rename.
The fix is to explicitly remove the watch to ensure the watch is resumed
under the original name.