The "focus" generated query string is wrong when multiple namespaces are selected in Network Traffic.   

Step to Reproduce:

1. Add more than one namespace in observe->network traffic.
   For example: netobserv and openshift-monitoring
   
2. click the force in troubleshoot-panel
3. check the query string

Actual result:

netflow:network:{SrcK8S_Type="Pod",SrcK8S_Namespace="netobserv","openshift-monitoring"}
 

Expected Result:
The troubleshoot provide a valid String which can be used to query data.