218e901de7
Change user/group creation to use flags to adduser/useradd to enforce it being a system user. Use system user defaults that auto-create a matching group. These changes allow us to remove all group creation code, and in doing so we also removed the code that finds available uid, gid integers and use post-creation query to gather the system-generated uid and gid. The only added complexity is that today distros don't auto-create subordinate ID ranges for a new ID if it is a system ID, so we now need to handle finding a free range and then calling the `usermod` tool to add the ranges for that ID. Note that this requires the distro supports the `-v` and `-w` flags on `usermod` for subordinate ID range additions. Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp) Upstream-commit: c18e7f3a0419e35aeab4eefa51f3c17fbd72381f Component: engine