Add regexp for container-engine lineinfile

This ensures that if the line already exists it will be updated with the
expected results from the installer.

roles/docker/tasks/systemcontainer_docker.yml

@@ -42,11 +42,14 @@
   ignore_errors: True
 
 # Set http_proxy, https_proxy, and no_proxy in /etc/atomic.conf
+# regexp: the line starts with or without #, followed by the string
+#         http_proxy, then either : or =
 - block:
 
     - name: Add http_proxy to /etc/atomic.conf
       lineinfile:
         dest: /etc/atomic.conf
+        regexp: "^#?http_proxy[:=]{1}"
         line: "http_proxy: {{ openshift.common.http_proxy | default('') }}"
       when:
         - openshift.common.http_proxy is defined
@@ -55,6 +58,7 @@
     - name: Add https_proxy to /etc/atomic.conf
       lineinfile:
         dest: /etc/atomic.conf
+        regexp: "^#?https_proxy[:=]{1}"
         line: "https_proxy: {{ openshift.common.https_proxy | default('') }}"
       when:
         - openshift.common.https_proxy is defined
@@ -63,6 +67,7 @@
     - name: Add no_proxy to /etc/atomic.conf
       lineinfile:
         dest: /etc/atomic.conf
+        regexp: "^#?no_proxy[:=]{1}"
         line: "no_proxy: {{ openshift.common.no_proxy | default('') }}"
       when:
         - openshift.common.no_proxy is defined