fix error that causes graph to be blank if there is no data in view
fix error that causes graph to be blank if there is no data in view

JFPayeur/emoncms,chaveiro/emoncms,vinipletsch/emoncms,thaipowertech/emoncms,emoncms/emoncms,euqip/emoncmsbase,chaveiro/emoncms,chaveiro/emoncms,jesjimher/emoncms,jesjimher/emoncms,arjenhiemstra/emoncms,arjenhiemstra/emoncms,jeremypoulter/emoncms,jeremypoulter/emoncms,inverse/emoncms,thaipowertech/emoncms,saydulk/emoncms,0ddie/emoncms,thaipowertech/emoncms,inverse/emoncms,jeremypoulter/emoncms,vinipletsch/emoncms,inverse/emoncms,vinipletsch/emoncms,saydulk/emoncms,inverse/emoncms,euqip/emoncms,emoncms/emoncms,JFPayeur/emoncms,emoncms/emoncms,arjenhiemstra/emoncms,euqip/emoncms,JFPayeur/emoncms,emoncms/emoncms,thaipowertech/emoncms,nmgeek/emoncms,nmgeek/emoncms,euqip/emoncmsbase,jesjimher/emoncms,emoncms/emoncms,jeremypoulter/emoncms,euqip/emoncms,saydulk/emoncms,nmgeek/emoncms,euqip/emoncms,sittipol123/emoncms,jesjimher/emoncms,sittipol123/emoncms,JFPayeur/emoncms,0ddie/emoncms,0ddie/emoncms,chaveiro/emoncms,sittipol123/emoncms,0ddie/emoncms,euqip/emoncmsbase