As discussed here
http://erlang.org/pipermail/erlang-questions/2012-December/071135.html
change the reltool spec to use the default sys-level mod_cond setting.

When developing Riak, we have found bugs and other issues due
to the number of platforms we support.

Here is an overview of the changes:
  -  Fix command-line syntax for commands to work on *BSD / Sun
  -  Add chkconfig and getpid to nodetool
  -  Replace platform specific 'kill' commands with a nodetool
	getpid method
  -  Fix RUNNER_USER settings to work on *BSD

* Typos and other minor bug fixes
* Add "attach" command (via -remsh)
* Add "upgrade" command to install a hot upgrade package
* Add "upgrade" subcommand to UNIX runner script as well

app.config has been a long standing erroneous file in rebar. Erlang/OTP
documentation suggests a sys.config file instead. This file is stored in
the releases/VSN directory. This does a few things but most importantly
it ensures your config (contained in the application environment)
survives a hot upgrade. It also has the advantage of allowing the
configuration of the application to be versioned along side the
application code. This patch flips rebar to use sys.config rather than
app.config.

Additionally it makes this flip to vm.args as well, making them
versioned just like sys.config.

This patch also includes runner script changes to support the old
etc/app.config config file location and support for Windows.

Thanks to mokele for the initial work and kick in the pants to make this
finially happen.

--HG--
extra : rebase_source : b8eaa05914