Fix: libpe_status: handle "requires" properly for anonymous clones

Previously, anonymous clone history was unpacked without regard for whether
"requires" was set to "quorum" or "nothing". This meant that apparently active
instances on unclean nodes consumed an instance number, even though such
instances should be considered inactive. Thus if we tried to start the instance
elsewhere, it might bring us above clone-max, causing us to stop an instance
that could run elsewhere.