Log skipped tasks to the job output

Right now these are only going to the executor debug log.

Change-Id: I3bb556e00ce7ebf1e806f1830c2881d2b0d2752d
diff --git a/zuul/ansible/callback/zuul_stream.py b/zuul/ansible/callback/zuul_stream.py
index 9622f24..078e1c9 100644
--- a/zuul/ansible/callback/zuul_stream.py
+++ b/zuul/ansible/callback/zuul_stream.py
@@ -284,6 +284,19 @@
         # Log an extra blank line to get space after each task
         self._log("")
 
+    def v2_runner_on_skipped(self, result):
+        reason = result._result.get('skip_reason')
+        if reason:
+            # No reason means it's an item, which we'll log differently
+            self._log_message(result, status='skipping', msg=reason)
+
+    def v2_runner_item_on_skipped(self, result):
+        reason = result._result.get('skip_reason')
+        if reason:
+            self._log_message(result, status='skipping', msg=reason)
+        else:
+            self._log_message(result, status='skipping')
+
     def v2_runner_on_ok(self, result):
         if (self._play.strategy == 'free'
                 and self._last_task_banner != result._task._uuid):