Commit cc50aa9dfb introduced GetResourceStats, a method which collected
all the statistics from various cgroup controllers, only to discard all
of the info collected except a single value (memory usage).
While one may argue that this method can potentially be used from other
places, this did not happen since it was added 4+ years ago.
Let's streamline this code and only collect what we need, i.e. memory
usage. Rename the method accordingly.
While at it, fix pkg/kubelet/cm/cgroup_manager_unsupported.go to not
instantiate a new error every time a method is called.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
f1aee7e049