* first round cleanup based on go-critic
* more issues resolved for ifelsechain and unlambda checks
* updated from master and gocritic found a new ifElseChain issue
* disable appendAssign. i reports false positives
* re-enabled go-critic appendAssign and disabled lint check at code line level
* fixed go-critic lint error
* fixed // nolint add gocritic specifically
Ran into difficulties trying to find the ideal solution for sharing
these counts between multiple satellite servers, so for now this is a
dumb solution storing recent space-usage changes in a big dumb in-memory
map with a big dumb lock around it. The interface used, though, should
allow us to swap out the implementation without much difficulty
elsewhere once we know what we want it to be.
