Execute salt '*' ceph.get_heartbeats，it return 'ceph.get_heartbeats' is not available.

Guys

I am getting a problem on CentOS7 , Salt version 2015.
after I installed all package and executed "salt-key -L" ,it was return ok.
```
[root@mon calamari]# salt-key -L
Accepted Keys:
mon
osd1
osd2
Denied Keys:
Unaccepted Keys:
Rejected Keys:
```

Then , when i was execute "salt '*' ceph.get_heartbeats", it was return error,
```
[root@mon calamari]# salt '*' ceph.get_heartbeats
osd1:
'ceph.get_heartbeats' is not available.
osd2:
'ceph.get_heartbeats' is not available.
mon:
'ceph.get_heartbeats' is not available.
ERROR: Minions returned with non-zero exit code
```

My salt version:
```
[root@mon calamari]# salt --version
salt 2015.8.13 (Beryllium)

[root@mon calamari]# salt-minion --version
salt-minion 2015.8.13 (Beryllium)
```

could any one tell me what happened with this, and how to fix it .thanks.

There is no repository file or test named in the report. Start by reproducing `salt '*' ceph.get_heartbeats` with Salt 2015.8.13 on the listed minions, then trace how that command is registered and determine whether the failure is version or configuration related; done means a verified fix or a clear explanation of the supported command.

Written by the indexing model from the issue text.