fix types
(transplanted from eec14a745dd738a98cfb83e86a2b077d4280e314)
Eliminate ?MEMORY_LIMIT_SCALING and make the ratio at which we page configurable. Note that I have changed the representation from a ratio-of-a-ratio to just a plain ratio (i.e. propertion of total memory, not proportion of the high watermark). I believe this will be easier to understand. Hence also the name vm_memory_paging_watermark, chosen by analogy with vm_memory_high_watermark.
Matthias convinced me to go with ratio-of-a-ratio.
Oops, I forgot that going back to vm_memory_monitor:get_memory_limit() means we can now have a limit of 0.0.
Updated changelogs for 3.1.2
Added tag rabbitmq_v3_1_2 for changeset bd3040292e1c
Delegate monitoring, with a fairly glaring hole.
A bit more faff, to deal with genuinely dying nodes.
Discard previously-discarded messages correctly
update package changelogs for 3.1.3
Added tag rabbitmq_v3_1_3 for changeset d61b25171094
Do the monitoring on the correct node(!) and remove all that nonsense about node-wide monitoring.
Remove unneeded assertion.
Recreate that assertion up one level in the call stack, since the callers may still care about it even though VQ itself does not.
BQ:is_empty/1.
Stem leak when master deals with discarded messages
Merge bug25624
stable to default
Optimisation for handling discarded deliveries
Ignore missing modules when performing HiPE compilation