We have to adapt the live accounting to allow the packages that use it
to differentiate about errors for being able to ignore them and make our
satellite resilient to Redis downtime.
For differentiating errors we should make changes in the live accounting
but also in the storage/redis.Client, however, we may need to do some
dirty workarounds or break other parts of the implementation that
depends on it.
On the other hand we want to get rid of the storage/redis.Client because
it has more functionality that the one that we are using and some
process has been started to remove it.
Hence, we have refactored the live accounting to directly use the Redis
client library for later on (in a future commit) adapt the satellite for
being resilient to Redis downtime.
Last but not least, a test for expired bandwidth keys have been added
and with it a bug was spotted and fix it.
Change-Id: Ibd191522cd20f6a9a15e5ccb7beb83a678e530ff
ce26616647