Require changes be open in check/gate

Only enqueue changes in the check or gate queues if they are "open"
in Gerrit.  This is required to break a test-comment loop caused by
the 'freshness' requirement on old abandoned changes.

Change-Id: I5e3c10295a71477e91e115d98a49a305d7e33adf

modules/openstack_project/files/zuul/layout.yaml

@@ -7,6 +7,8 @@ pipelines:
     failure-message: Build failed.  For information on how to proceed, see https://wiki.openstack.org/wiki/GerritJenkinsGit#Test_Failures
     manager: IndependentPipelineManager
     precedence: low
+    require:
+      open: True
     trigger:
       gerrit:
         - event: patchset-created
@@ -54,6 +56,8 @@ pipelines:
     failure-message: Build failed.  For information on how to proceed, see https://wiki.openstack.org/wiki/GerritJenkinsGit#Test_Failures
     manager: DependentPipelineManager
     precedence: normal
+    require:
+      open: True
     trigger:
       gerrit:
         - event: comment-added
@@ -193,6 +197,8 @@ pipelines:
       https://wiki.openstack.org/wiki/GerritJenkinsGit#Test_Failures
     manager: IndependentPipelineManager
     precedence: low
+    require:
+      open: True
     trigger:
       gerrit:
         - event: patchset-created