Delete infra-check pipeline

This is no longer used anywhere, lets delete it.

Change-Id: I965ea859de43fb4d4bd4b682b56a67167c170af7
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

zuul.d/pipelines.yaml

@@ -54,52 +54,6 @@
         status: 'failure'
       mysql:
 
-- pipeline:
-    name: infra-check
-    description: |
-      Newly uploaded patchsets enter this pipeline to receive an
-      initial +/-1 Verified vote.
-    manager: independent
-    precedence: high
-    trigger:
-      gerrit:
-        - event: patchset-created
-        - event: change-restored
-        - event: comment-added
-          comment: (?i)^(Patch Set [0-9]+:)?( [\w\\+-]*)*(\n\n)?\s*recheck
-        - event: comment-added
-          require-approval:
-            - Verified: [-1, -2]
-              username: zuul
-          approval:
-            - Workflow: 1
-      github:
-        - event: pull_request
-          action:
-            - opened
-            - changed
-            - reopened
-        - event: pull_request
-          action: comment
-          comment: (?i)^\s*recheck\s*$
-    start:
-      github:
-        status: pending
-        comment: false
-    success:
-      gerrit:
-        # Note that gerrit keywords are case-sensitive.
-        Verified: 1
-      github:
-        status: 'success'
-      mysql:
-    failure:
-      gerrit:
-        Verified: -1
-      github:
-        status: 'failure'
-      mysql:
-
 - pipeline:
     name: gate
     description: |