Update instead of replacing the environment file

Currently the entire environment file is replaced,
which may remove any existing configuration on the
hosts including any pre-existing proxy configurations
and anything else the deployer may have put there.

This method replaces it with an additive process which
respects pre-existing content, but still allows the
global_environment_variables variable changes to be
fully reflected in the resulting environment file.

Change-Id: Ida3897f2553491913a3183e67b6503bed5281d5e

tasks/openstack_proxy_settings.yml

@@ -13,8 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- name: Install host proxy settings
-  template:
+- name: Add global_environment_variables to environment file
+  blockinfile:
     dest: "/etc/environment"
-    src: "environment.j2"
-    mode: "0644"
+    state: present
+    marker: "# {mark} Managed by OpenStack-Ansible"
+    insertbefore: EOF
+    block: "{{ lookup('template', 'environment.j2') }}"

templates/environment.j2

@@ -1,10 +1,8 @@
-# {{ ansible_managed }}
-
 PATH="{{ openstack_host_environment_path | join(':') }}"
 {% if global_environment_variables is defined %}
-{% for key, value in global_environment_variables.iteritems() %}
-{% if value %}
+{%   for key, value in global_environment_variables.iteritems() %}
+{%     if value %}
 {{ key }}={{ value }}
-{% endif %}
-{% endfor %}
+{%     endif %}
+{%   endfor %}
 {% endif %}