virt-inspector --fish: Fix incorrect '-a' parameter (RHBZ#512709)

virt-inspector --fish: Fix incorrect '-a' parameter (RHBZ#512709)

virt-inspector --fish dom
virt-inspector --ro-fish dom

Both of the above commands give incorrect results if run on a
libvirt domain, eg:

$ virt-inspector --ro-fish RHEL54Betax64
==> --ro -a RHEL54Betax64 -m /dev/VolGroup00/LogVol00:/ -m /dev/sda1:/boot
            ^^^^^^^^^^^^^

This is because the current code just prints back the original @ARGV
parameters.

This patch fixes this by getting the image names instead.