MAINTAINER: Fix the description of LVSB sub testset.

It seems a error from copy-paste, the description of LVSB sub tests
is "Libvirt subtests".

This patch change it to "LVSB subtests".

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
virttest.standalone_test: Close file handler at the end of test

Free up resources at the end of each test, as we should
have done anyway.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>