cmd/watcher: record files changed in each commit
cmd/watcher: record files changed in each commit

Change-Id: I1c0140c564689d6f673494ddaf7c3d7cccd30397
Reviewed-on: https://go-review.googlesource.com/10320
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

evandbrown/build,proppy/build,golang/build,proppy/build,evandbrown/build,golang/build,evandbrown/build,golang/build,proppy/build,golang/build,proppy/build