Being able to recognize that "par" is reliably initialized on the 1st
loop iteration requires not overly old compilers.
Fixes: 7809132b1a ("tools/xen-9pfsd: add 9pfs response generation support")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>