Description of problem:
I've tried to call "externalusers" function with result:
[{"username":"","email":"","role":"","groups":null,"type":0,"status":false,"firstname":"","lastname":"","notificationenabled":false},{"username":"admin","email":"","role":"","groups":null,"type":0,"status":false,"firstname":"","lastname":"","notificationenabled":false},{"username":"testldap","email":"","role":"","groups":null,"type":0,"status":false,"firstname":"","lastname":"","notificationenabled":false}]

There are these issues:
1) there is empty user in result
2) default values of some attributes are not valid values in user list for USM:
 a) "role":""
 b) "groups":null
3) I think that email, firstname nad lastname are not imported from LDAP

Because of these issues admin cannot import some users from LDAP directly into USM.

Version-Release number of selected component (if applicable):
rhscon-core-0.0.7-0.1.alpha1.el7.x86_64
rhscon-ui-0.0.6-0.1.alpha1.el7.noarch
rhscon-ceph-0.0.5-0.1.alpha1.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. install and setup ldap server
2. add some users
3. configure ldap authentication to USM
4. call /externalusers function

Actual results:
There are issues in result of externalusers function.

Expected results:
It will be possible to add some users from LDAP into USM. All attributes will have default value as in /users function result or will have value as in LDAP.

Additional info:
/users function result for compare:
[{"username":"admin","email":"admin@localhost","role":"admin","groups":[],"type":0,"status":true,"firstname":"","lastname":"","notificationenabled":false}]