message-tagging-services: set env var USERNAME for fedmsg to publish messages

Refer to the comment inside code for details.

Signed-off-by: Chenxiong Qi <cqi@redhat.com>

roles/openshift-apps/message-tagging-service/templates/deployment.yml

@@ -20,10 +20,19 @@ spec:
       - name: mts
         image: quay.io/factory2/message-tagging-service:{{ quay_tag }}
         env:
+        # Set this environment variable for fedmsg to publish a message to
+        # fedmsg hub.
+        # Some details:
+        # When call publish function to publish a message, fedmsg requires to
+        # get current user's name by calling getpass.getuser function, which
+        # then tries to get name from several environment variables firstly, if
+        # fail on all of those variables, it gets current user id and tries to
+        # get name from local user database /etc/passwd.
+        # Without this variable set manually, user id does not exist in
+        # /etc/passwd, and there is also no environment variables set to make
+        # getpass.getuser work normally.
         - name: USERNAME
           value: mts
-        - name: LOGNAME
-          value: mts
         ports:
         - containerPort: 8080
         volumeMounts: