Make admin user for mongodb optional

Change-Id: I8279e79eac334dbd0007f17eb645b24fdce5005f
PROD-related: PROD-19892

salt/files/minion.conf

@@ -143,9 +143,13 @@ mysql.charset: 'utf8'
 {%- if pillar.get('mongodb', {}).server is defined %}
 mongodb.host: 'localhost'
 mongodb.port: {{ pillar.mongodb.server.bind.port }}
+{%- if pillar.mongodb.server.get('admin', {}).user is defined %}
 mongodb.user: '{{ pillar.mongodb.server.admin.user }}'
+{%- endif %}
+{%- if pillar.mongodb.server.get('admin', {}).password is defined %}
 mongodb.password: '{{ pillar.mongodb.server.admin.password }}'
 {%- endif %}
+{%- endif %}
 
 {%- if pillar.get('postgresql', {}).server is defined %}
 postgres.user: 'postgres'