Remove python 2.6 from pbr

Remove python 2.6 jobs from pbr, remove also the definition in Jenkins
and the template in zuul for it.

Change-Id: I3938091b7daf62ce15b026f4111b234b112e691e

jenkins/jobs/projects.yaml

@@ -4205,7 +4205,6 @@
     jobs:
       - openstack-publish-jobs
       - python-jobs
-      - 'gate-{name}-python26'
       - pypi-jobs
       - 'lib-forward-testing-{name}'
 

jenkins/jobs/python-jobs.yaml

@@ -106,35 +106,6 @@
 
     node: '{node}'
 
-- job-template:
-    name: 'gate-{name}-python26'
-
-    wrappers:
-      - build-timeout:
-          timeout: 70
-      - timestamps
-
-    builders:
-      - print-template-name:
-          template-name: "{template-name}"
-      - shell: |
-          #!/bin/bash -xe
-          if ! rpm -ql libffi-devel >/dev/null ; then
-              sudo yum install -y libffi-devel
-          fi
-          rpm -ql libffi-devel
-      - revoke-sudo
-      - gerrit-git-prep
-      - python26
-      - assert-no-extra-files
-
-    publishers:
-      - test-results
-      - console-log
-      - zuul-swift-test-results-with-console
-
-    node: bare-centos6
-
 - job-template:
     name: 'gate-{name}-python27'
 

zuul/layout.yaml

@@ -352,14 +352,6 @@ project-templates:
     gate:
       - 'gate-{name}-python34-constraints'
 
-  # Python 2.6 is deprecated, these jobs will be removed once no
-  # OpenStack projects needs it (once Juno is retired).
-  - name: python26-jobs
-    check:
-      - 'gate-{name}-python26'
-    gate:
-      - 'gate-{name}-python26'
-
   - name: pypy-jobs
     check:
       - 'gate-{name}-pypy'
@@ -2289,7 +2281,6 @@ projects:
     template:
       - name: merge-check
       - name: python-jobs
-      - name: python26-jobs
       - name: python3-jobs
       - name: publish-to-pypi
       - name: lib-forward-testing