Description of problem:

When a cluster is created manually without any nodes or bricks and when such a cluster id is defined as part of storage class, pvc creation fails with 'Error calling v.allocBricksInCluster: Id not found'. Looks like we just return the error received from the function. A better error message should be provided.

p.s., This bug is more of an enhancement, uncovered during negative test. Regular workflow of CNS will not end up in this scenario.

[root@dhcp46-201 ~]# heketi-cli cluster info 75f2bdc4e362b8f78833af932f0ebcf9
Cluster id: 75f2bdc4e362b8f78833af932f0ebcf9
Nodes:

[root@dhcp46-201 ~]# cat storageclass_voltype 
apiVersion: storage.k8s.io/v1beta1
kind: StorageClass
metadata:
  name: voltypenegative 
provisioner: kubernetes.io/glusterfs
parameters:
  resturl: "http://heketi-storage-project.cloudapps.mystorage.com"
  restuser: "test"
  clusterid: "75f2bdc4e362b8f78833af932f0ebcf9"

[root@dhcp46-201 ~]# oc describe pvc/clusterid
Name:		clusterid
Namespace:	storage-project
StorageClass:	voltypenegative
Status:		Pending
Volume:		
Labels:		<none>
Capacity:	
Access Modes:	
Events:
  FirstSeen	LastSeen	Count	From				SubObjectPath	Type		Reason			Message
  ---------	--------	-----	----				-------------	--------	------			-------
  21s		11s		2	{persistentvolume-controller }			Warning		ProvisioningFailed	Failed to provision volume with StorageClass "voltypenegative": glusterfs: create volume err: error creating volume Error calling v.allocBricksInCluster: Id not found.

Version-Release number of selected component (if applicable):
# rpm -qa | grep 'heketi'
heketi-client-4.0.0-1.el7rhgs.x86_64
# oc version
oc v3.5.0.37
kubernetes v1.5.2+43a9be4
features: Basic-Auth GSSAPI Kerberos SPNEGO

openshift v3.5.0.37
kubernetes v1.5.2+43a9be4


How reproducible:
always

Steps to Reproduce:
provided along with the description