Rename the errors package to errs

This makes it less confusing since there is an errors package in the standard
library as well. Now there can be no confusion which one is being used where.

Change-Id: 9b8bf7fb88
errs: Rename and change the Log function

Rename the Log function to LogAndReturn and change the signature to return the
error that was passed into the function as the argument. This helps to save some
lines of code, to use return LogAndReturn(err).

Change-Id: c580ab28b6
wip

Change-Id: f7694d751c
Story-Id: SF-6