utils_libvirtd: Make service_libvirtd_control() only for local host.

As service_libvirtd_control() exists here for compatibility, we need
keep it simple and used limitedly.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
utils_conn: Adapt utils_conn to new and standard usage of libvirtd service.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
staging/service: Get rid of root requirement to get name of init process.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Merge pull request #1584 from yangdongsheng/utils_libvirtd

Fix for staging/service and virttest/utils_libvirtd.