rename nets to libvirt_nets for readability

Change-Id: I8a07e3cb2b730031a1403b3bbad487d58ee0fc52
Signed-off-by: ibarkan <ibarkan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/35923
Reviewed-by: Ondřej Svoboda <osvoboda@redhat.com>
Tested-by: Ondřej Svoboda <osvoboda@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>