Per convo on IRC with jeblair, removing gate

Removes the gate pipeline from the Zuul layout.yaml file. No external
systems are voting on the gate pipeline, so just remove it. Also removes
the precedence keyword from the check pipeline and the includes section.

etc/zuul/layout.yaml

@@ -1,12 +1,8 @@
-includes:
-  - python-file: openstack_functions.py
-
 pipelines:
   - name: check
     description: Newly uploaded patchsets enter this pipeline to receive an initial +/-1 Verified vote from Jenkins.
     failure-message: Build failed.  For information on how to proceed, see https://wiki.openstack.org/wiki/GerritJenkinsGit#Test_Failures
     manager: IndependentPipelineManager
-    precedence: low
     trigger:
       gerrit:
         - event: patchset-created
@@ -26,29 +22,6 @@ pipelines:
       gerrit:
         verified: -1
 
-  - name: gate
-    description: Changes that have been approved by core developers are enqueued in order in this pipeline, and if they pass tests in Jenkins, will be merged.
-    failure-message: Build failed.  For information on how to proceed, see https://wiki.openstack.org/wiki/GerritJenkinsGit#Test_Failures
-    manager: DependentPipelineManager
-    precedence: low
-    trigger:
-      gerrit:
-        - event: comment-added
-          approval:
-            - approved: 1
-        - event: comment-added
-          #TODO: This coment regex is likely out-of-date
-          comment_filter: (?i)^\s*reverify( (?:bug|lp)[\s#:]*(\d+))\s*$
-    success:
-      gerrit:
-        verified: 2
-        submit: true
-    failure:
-      gerrit:
-        verified: -2
-    window-floor: 20
-    window-increase-factor: 2
-
 projects:
   - name: openstack-dev/sandbox
     check:
@@ -58,10 +31,3 @@ projects:
       # Uncomment this job when you have a jenkins slave running and want to
       # test a full Tempest run within devstack.
       #- dsvm-tempest-full
-    gate:
-      # Remove this after successfully verifying communication with upstream
-      # and seeing a posted successful review.
-      - noop-check-communication
-      # Uncomment this job when you have a jenkins slave running and want to
-      # test a full Tempest run within devstack.
-      #- dsvm-tempest-full