libxl: strdup disk path before put it in qemu args array.

libxl: strdup disk path before put it in qemu args array.

In libxl_build_device_model_args_new, the path to the disk image are
freeed before there was actually use to make the arguments list of Qemu.
The patch strdups it.

This patch also changes argv[0] of the device model.
Now, it is the conventional argv[0], so is value come from
info->device_model.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
committer: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/libxl/libxl.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)