Remove filterclear

[rebroad]

This message (filterclear) isn't included in the reasons for moving bloom services into a opt-out service.

Also, filterclear is a useful way for nodes to start with TX relay off and to request TX relay later. (e.g. during IBD).

Discussed in bitcoin/bitcoin#8709

[luke-jr]

@TheBlueMatt @petertodd

I think it's too late to change this, though...?

[TheBlueMatt]

The context is bitcoin/bitcoin#8709
I support the idea, but the text needs to note that some versiond do ban for filterclear, but it is very strongly recommended (maybe MUST) that new versions do not do so.

[petertodd]

Given the low consequences for connecting to a peer without this change - getting disconnected - I think it's reasonable to change this behavior and just phase it in over time. Also as @pstratem notes, reconnecting after IBD is sufficient for now: bitcoin/bitcoin#8709 (comment) (which retry logic in your implementation may very well do anyway!)

[luke-jr]

So is that an ack, or does it need changes? (What's the status here?)

[TheBlueMatt]

This needs some text to note that some nodes on the network will additionally disconnect for filterclear, but new implementations MUST NOT do so.

[luke-jr]

@rebroad Please either finish or close this...

[rebroad]

@TheBlueMatt @petertodd

I think it's too late to change this, though...?

i think it is now!