Fix warn logs in gas analyzer

[pgebal]

Gas analyzer prints lot of warn logs because it can't get transaction receipt by txhash. Find the reason why that happens.

Also consider decreasing log level and print warn only when maximum number of retries is reached.

logs: https://app.datadoghq.com/logs?cols=core_host%2Ccore_service&context_event=AQAAAXKur5tgbFfU4QAAAABBWEt1cjZMLTJRWkpJbUhZVGdBQw&event&from_ts=1592065223765&index=&live=false&messageDisplay=inline&query=host%3Agke-prod-a69c763f-ma-default-nodepool-f6df2b49-wdx4.c.omisego-production.internal+service%3Achild_chain+container_id%3A1334edeba23c9c5cc8b79d002010fe4dd0bcb94ce072349f7c04823134c3c0d1+filename%3A0.log+status%3Awarn&stream_sort=desc&to_ts=1592067600000

[InoMurko]

the warn logs come out because transactions that are not accepted don't have information about used gas.