lxc: remove duplicate header files
lxc: remove duplicate header files

"#include vircgroup.h" appears in both lxc_cgroup.h and
lxc_cgroup.c, and lxc_cgroup.c contains lxc_cgroup.h,
so remove the duplicate declarations.

Signed-off-by: Mao Zhongyi <c7ea2309a237789bbb43a52c8d1e0a7c5649c50c@cmss.chinamobile.com>
Signed-off-by: Zhang Shengju <732ab4d9aa3a9cc34167137405caff6df7bae7ae@cmss.chinamobile.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

jfehlig/libvirt,nertpinx/libvirt,jardasgit/libvirt,jfehlig/libvirt,crobinso/libvirt,fabianfreyer/libvirt,libvirt/libvirt,jardasgit/libvirt,zippy2/libvirt,zippy2/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,olafhering/libvirt,olafhering/libvirt,olafhering/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,jardasgit/libvirt,nertpinx/libvirt,jardasgit/libvirt,crobinso/libvirt,fabianfreyer/libvirt,libvirt/libvirt,olafhering/libvirt,jfehlig/libvirt,zippy2/libvirt,libvirt/libvirt,fabianfreyer/libvirt,zippy2/libvirt,nertpinx/libvirt,crobinso/libvirt,jardasgit/libvirt,fabianfreyer/libvirt