Use current-patchset pipeline requirement

This should stop zuul comment loops when people comment on old
patchsets.

Change-Id: Ide08555bc588fe58245b0a8aa714fde594aa968b
NOTE: Requires https://review.openstack.org/92942 be deployed.

modules/openstack_project/files/zuul/layout.yaml

@@ -9,6 +9,7 @@ pipelines:
     precedence: low
     require:
       open: True
+      current-patchset: True
     trigger:
       gerrit:
         - event: patchset-created
@@ -58,6 +59,7 @@ pipelines:
     precedence: normal
     require:
       open: True
+      current-patchset: True
     trigger:
       gerrit:
         - event: comment-added
@@ -199,6 +201,7 @@ pipelines:
     precedence: low
     require:
       open: True
+      current-patchset: True
     trigger:
       gerrit:
         - event: patchset-created