Change definitions of $1,$2,$3 to match djb's redo.

If you use "redo --old-args", it will switch back to the old
(apenwarr-style) arguments for now, to give you time to update your .do
scripts.  This option will go away eventually.

Note: minimal/do doesn't understand the --old-args option.  If you're using
minimal/do in your project, keep using the old one until you update your use
of $1/$2, and then update to the new one.

apenwarr-style default.o.do:
   $1      foo
   $2      .o
   $3      whatever.tmp

djb-style default.o.do:
   $1      foo.o
   $2      foo
   $3      whatever.tmp

apenwarr-style foo.o.do:
   $1      foo.o
   $2      ""
   $3      whatever.tmp

djb-style foo.o.do:
   $1      foo.o
   $2      foo.o  (I think?)
   $3      whatever.tmp

t/curse/default.n2.do

@@ -1,6 +1,6 @@
-echo n2-$1
-echo $1 >>$1.count
-echo $1 >>in.countall
+echo n2-$2
+echo $2 >>$2.count
+echo $2 >>in.countall
 
 # we deliberately use 'redo' here instead of redo-ifchange, because this *heavily*
 # stresses redo's locking when building in parallel.  We end up with 100