parallel test: change port value to puppet_7_node

Use the port value for puppet_7_node, which is now used in testing
instead of puppet_6_node.

This plan is tightly coupled with the test in
spec/integration/parallel_spec.rb "finishes executing the block then
raises an error when there's an error".

In 573cdb5 the puppet 6 node was
removed from testing and the puppet 7 node was used to replace it.
This plan relied on matching the port value of the puppet 6 node to
decide to run a failing task, but the puppet 7 node has a different port
number.

Author: austb

spec/fixtures/parallel/parallel/plans/error.pp

@@ -3,7 +3,7 @@
 ) {
   $ts = get_targets($targets)
   parallelize($ts) |$t| {
-    if $t.port == 20024 {
+    if $t.port == 20025 {
       run_task('error::fail', $t)
     } else {
       run_task('parallel', $t, 'time' => 0, 'val' => 'a')