Jussi Kukkonen authored May 29, 2018 and Ariadne Conill committed Jul 02, 2018

It's common for a pre-install script to do something like
    addgroup -S group 2>/dev/null
When apk installs files after this, it sets the owner/group based on id cache
but currently the id cache is stale and doesn't contain the new group at that
point: instead the file will be installed with gid that the build host
happened to have for that group -- on target this might mean a non-existing
group or a completely different group.

We can't know if the script really did modify id cache contents so make sure
to reset the id cache on every script execution.