qemu-img: fix missing space in qemu-img check output

The qemu-img check fragmentation printf() is missing a space before the
'=' sign.  The human output is not guaranteed to be stable and we are
not aware of screen scrapers, so add the missing space.

Also fix the missing indentation of the printf() arguments.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
