Ensure riak_repl service is up across the board

Trying to use the repl features before newly started nodes have
riak_repl completely initialized leads to all sorts of nasty crashes and
noise. Frequently it makes fullsync stuck forever, which makes a lot of
the tests fail.

This also tweaks the AAE fullsync tests to remove assumptions about
failure stats when AAE transient errors occur. The behavior in the
handling of those errors has changed recently with the introduction of
soft exits.

Also, the AAE fs test expected AAE transient errors to still allow fullsync
to complete through them. Now we wait for AAE to resolve those issues
forever by default to allow possibly long AAE tree builds to finish and then
 proceed with the fullsync.