Add a dockerfile for build jenkins development

* Also make sure /var/run/docker exists so that we can create docker.pid
  for /usr/bin/daemon to manage

docker/build/jenkins_build/Dockerfile

+FROM edxops/xenial-common:latest
+MAINTAINER edxops
+
+USER root
+RUN apt-get update
+
+ADD . /edx/app/edx_ansible/edx_ansible
+WORKDIR /edx/app/edx_ansible/edx_ansible/docker/plays
+COPY docker/build/tools_jenkins/ansible_overrides.yml /
+RUN PYTHONUNBUFFERED=1 /edx/app/edx_ansible/venvs/edx_ansible/bin/ansible-playbook -v jenkins_build.yml -i '127.0.0.1,' -c local -e@/ansible_overrides.yml -vv -t 'install'
+
+CMD /bin/su -l jenkins --shell=/bin/bash -c "/usr/bin/daemon -f --name=jenkins --inherit --env=JENKINS_HOME=/edx/var/jenkins --output=/var/log/jenkins/jenkins.log --pidfile=/var/run/jenkins/jenkins.pid -- /usr/bin/java  -jar /usr/share/jenkins/jenkins.war --webroot=/var/cache/jenkins/war --httpPort=8080 --ajp13Port=-1"

docker/build/jenkins_build/ansible_overrides.yml

+---
+DOCKER_TLD: "edx"
+

docker/plays/jenkins_build.yml

+- name: Deploy the build jenkins
+  hosts: all
+  become: True
+  gather_facts: True
+  vars:
+    serial_count: 1
+  serial: "{{ serial_count }}"
+  roles:
+    - common_vars
+    - docker
+    - jenkins_build

playbooks/roles/jenkins_common/tasks/main.yml

@@ -50,6 +50,16 @@
     - install
     - install:system-requirements
 
+- name: Create /var/run/jenkins
+  file:
+    path: "/var/run/jenkins"
+    state: directory
+    owner: "{{ jenkins_common_user }}"
+    group: "{{ jenkins_common_group }}"
+  tags:
+    - install
+    - install:system-requirements
+
 - name: Delete any existing jenkins-configuration folders to avoid unwanted configuration
   file:
     path: '{{ item }}'

util/parsefiles_config.yml

@@ -31,3 +31,4 @@ weights:
   - notifier: 2
   - mongo: 1
   - devpi: 1
+  - jenkins_build: 8