…t were unintentionally attributed to the first function

Various fixes for edoc

Reviewed-by: reiddraper

Problem: transient failures of aae, such as trees not yet built or locks not
being aquired, would cause an aae fullsync process to exit abnormally. This
could happen several times in a row, creating log spam.

Resolution: the concept of soft_exit. A soft_exit is a message sent from a soon
to be exiting process to a soft_linked process. The exiting process would then
exit normally, while any soft_linked processes could handle the soft_exit
message in a similar fashion as an exit message. This would indicate an exit
reason that should be handled, but not bad enough to have the system logger
know about it.

The soft_exit message sent from the aae worker to the fscoordinator is
as simple as `{soft_exit, pid(), term()}'.

The current implementation is not generic. There can only one soft_link to
the aae, and there's no general mechanism to use soft_link's or soft_exits
elsewhere in the code base. Sorry.

Another change rolled into this is consistent use of a #partition_info record
in the fscoordinator, and error tracking the fscoordinator's state. By swapping
to useing a single data structure in the partition queue, whereis waiting list,
and purgatory queues it makes it easier to understand the fscordinator (as
there is less code modify structures).

This is a forward port of the fix done for 1.4. Conflicts favor existing code
where it does not directly effect the fix.

Conflicts:
	Makefile
	rebar.config
	src/riak_repl2_fssource.erl
	src/riak_repl2_rtq_proxy.erl
	src/riak_repl_aae_source.erl
	test/riak_core_cluster_mgr_tests.erl

Increment_error_dict expects the partition, elementN of error dict, and the
state. It pulls the dict out of the state so it put it back in place, thus just
returning the state. So this call that passed the dict in was wrong.

When a partition is not available, perhaps after a number of retries,
the error exits stat should be incremented. Also, the retry exits stat
should be incremented on each retry.  This was discovered when
backporting the repl_location_failures riak_test.

The one in riak_repl2_fssource is a legit bug in the code

…nsient-aae-fs-failures

Implement soft_exit, primarily for aae_fullsyn.

Reviewed-by: engelsanchez

Conflicts:
	dialyzer.ignore-warnings
	rebar.config

Conflicts:
	src/riak_repl2_fscoordinator.erl

Develop 2.0 merge.

Reviewed-by: seancribbs

Add support for Erlang 17.

Reviewed-by: andrewjstone

* `standard_error` group leader cannot be used because it is not
  forwarded to the RPC caller.
* Fix newlines around top-level usage and V2 warnings

These settings were extracted from the replication code, but have not
been vetted or necessarily named properly. Many of them are slated to be
removed or changed for future versions of riak_repl. To promote a
setting to the main schema, one should write documentation and tests to
cover the setting.

deprecation/upgrade warnings