fix ansible 2.x error

playbooks/roles/edxlocal/tasks/main.yml

@@ -25,7 +25,7 @@
     password: "{{ item.pass }}"
     priv: "{{ item.db }}.*:ALL"
     append_privs: yes
-  when: item.db != None and item.db }} != ''
+  when: item.db != None and item.db != ''
   with_items: "{{ edxlocal_database_users }}"
 
 - name: setup the migration db user