Revert "Post comments"

This reverts commit 0420f2d.

Author: mnasiadka

zuul.d/pipelines.yaml

@@ -21,19 +21,19 @@
     start:
       github:
         check: 'in_progress'
-        comment: true
+        comment: false
     success:
       github:
         check: 'success'
-        comment: true
+        comment: false
     failure:
       github:
         check: 'failure'
-        comment: true
+        comment: false
     dequeue:
       github:
         check: 'cancelled'
-        comment: true
+        comment: false
 
 - pipeline:
     name: gate