Sometimes alert count creates None entry in clusters
Sometimes alert count creates None entry in clusters

tendrl-bug-id: Tendrl/node-agent#755

(e.g)
clusters/None/nodes/{nid}/alert_counters

Signed-off-by: GowthamShanmugam <8c664c2cfb272eb6524e212187e1d749ad3db0b4@redhat.com>

r0h4n/node-agent,Tendrl/node-agent,r0h4n/node-agent,Tendrl/node-agent,r0h4n/node-agent,Tendrl/node-agent,Tendrl/node_agent,Tendrl/node_agent