Seems like a simple typo - it has been "format=" since the flag
was introduced, but we added it as "fmt=".
Signed-off-by: NMark McLoughlin <markmc@redhat.com>

* tests/qemuxml2argvtest.c (testCompareXMLToArgvFiles): Adjust the
code that creates "actual" output, so that it too produces a
newline-terminated buffer.
* tests/qemuxml2argvdata/*.args: Append a newline to each, via:
for i in $(find|grep '\.args$'); do echo >> $i;done

handling code.  In particular, if you had a section of XML like:

    <disk type='file' device='cdrom'>
      <target dev='hdc' bus='ide'/>
      <readonly/>
    </disk>

This used to work with older libvirt, but now fails.  This is because we are
actually passing the literal string (null) to the qemu command-line, which qemu
barfs on.  This patch fixes it up by making it blank, which allows qemu to
continue on it's merry way.
Signed-off-by: NChris Lalancette <clalance@redhat.com>