All the go-lint work forced any existing "Uid" -> "UID", but seems to
not have the same rules for Gid, so stat package has calls UID() and
Gid().
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
pkg/archive contains code both invoked from cli (cross platform) and
daemon (linux only) and Unix-specific dependencies break compilation on
Windows. We extracted those stat-related funcs into platform specific
implementations at pkg/system and added unit tests.
Signed-off-by: Ahmet Alp Balkan <ahmetb@microsoft.com>