Re: [libvirt] [PATCH 4/8] Refactor cgroups to allow a group per driver to be managed directly

Allow the driver level cgroup to be managed explicitly by the hypervisor drivers, in order to detect whether to enable or disable cgroup support for domains. Provides better error reporting of failures. Also allow for creation of cgroups for unprivileged drivers if controller is accessible by the user. * src/cgroup.c, src/cgroup.h: Add an API to obtain a driver cgroup * src/lxc_conf.h, src/lxc_controller.c, src/lxc_driver.c: Obtain a driver cgroup at startup and use that instead of re-creating everytime. * src/util.c, src/util.h, src/libvirt_private.syms: Add a virGetUserName() helper