virfirewalltest: Shuffle the code around to remove a loop

virfirewalltest: Shuffle the code around to remove a loop

We are already looping over the arguments to construct the list, so we
can add them to fwBuf right away rather than in an extra loop if we move
some of the 'fwBuf' parts earlier and merge the two loops.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>