daemon: ensure cache files for system users are processed

At the moment we skip cache files for system users.  That
doesn't make much sense; if there's a cache file we should
be using it.

This commit changes the code to read cache files, even for
system users, and so lets root have a non-default session.

Closes: #65
1 job for master in 1 minute and 20 seconds (queued for 1 second)
Status Job ID Name Coverage
passed #267994