virt-libvirt: Fix bug of virsh_save.cfg.

Last line said that No newline at end of file.
When we create subtests.cfg in libvirt project,
the end of virsh_save will like this:
(omit)
save_libvirtd = "off"    - virsh_setmem:
(omit)

Signed-off-by: Yu Mingfei<yumingfei@cn.fujitsu.com>