We have an alert on `repair_too_many_nodes_failed` which fires too
frequently. Every time so far, it has been because of a network blip of
some nature on the satellite side.
Satellite operators are expected to have other means in place for
alerting on network problems and fixing them, so it's not necessary for
the repair framework to act in that way.
Instead, in this change, we change the way that
`repair_too_many_nodes_failed` works. When a repair fails, we collect
piece fetch errors by type and determine from them whether it looks like
we are having network problems (most errors are connection failures,
possibly also some successful connections which subsequently time out)
or whether something else has happened.
We will now only emit `repair_too_many_nodes_failed` when the outcome
does not look like a network failure. In the network failure case, we
will instead emit `repair_suspected_network_problem`.
Refs: https://github.com/storj/storj/issues/4669
Change-Id: I49df98da5df9c606b95ad08a2bdfec8092fba926
7f1cad6faf