UT fixes.

Not changing their semantics, but actually making them more correct.

* RemoteAuthTest: it does not matter where auth is set for reposes, but
  once proxy404 comes it, it will matter, as without auth the proxies
  autoblocks (rightfully, as it is basically wrong config).
* RemoteStorageSettingsInheritanceTest with proxy404 revealed a nasty bug:
  "change detection" was very wrong, when child generation ran away from
  parent value (as is case with proxy404).