When existing miner is connected to an existing aggregator, indicators are not pushed

[jtschichold]

Description

When an already existing miner is connected to an already existing aggregator, the indicators inside the miner are not pushed to the aggregator.

How to reproduce

Install the following config and commit:

nodes:
  miner_1:
    inputs: []
    output: true
    prototype: spamhaus.DROP
  miner_2:
    inputs: []
    output: true
    prototype: spamhaus.EDROP
  IPv4Aggregator:
    inputs:
      - miner_1
    output: true
    prototype: stdlib.aggregatorIPv4Generic
  IPv4Feed:
    inputs:
      - IPv4Aggregator
    output: false
    prototype: stdlib.feedHCWithValue

When the engine is running again, connect IPv4Aggregator to miner_2 and commit again.

Expected the number of indicators in IPv4Aggregator should increase and should be roughly the sum of the indicators in miner_1 and miner_2

Result number of indicators in IPv4Aggregator does not increment, and there no UPDATEs are produced by miner_2