generic/398: filter out extra string from newer mv

generic/398: filter out extra string from newer mv

mv command produces a leading string "renamed" from some time.
This breaks generic/398. Adding a _filter_mv to filter it out.
Tested this patch on Fedora 28.

sh-4.2$ rpm -qf /usr/bin/mv
coreutils-8.22-23.el7.x86_64
sh-4.2$ mv -v 1 2
‘1’ -> ‘2’
sh-4.2$

h-4.4# rpm -qf /usr/bin/mv
coreutils-8.30-5.el8.x86_64
sh-4.4# mv -v 1 2
renamed '1' -> '2'
sh-4.4#

igned-off-by: Xiong Murphy Zhou <xzhou@redhat.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>