bos: remove smail-notifier
smail-notifier is a sample program that is undocumented and has not
been well maintained. It produces copious compiler warnings, and
would require effort to bring the code up to decent coding practices.
The bosserver provides a -notifier feature that can be used for
notifications, but that feature does not depend on this sample program.
Removed the code, cleaned up the Makefiles and .gitignore.
Change-Id: I6bd56559121d12ad007acc571b6653aa934eb97f
Reviewed-on: https://gerrit.openafs.org/13509
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>