cleanup(influxdb_08): removed influxdb 0.8 data source as an built in official data source, moved it to an external plugin repo, https://github.com/grafana/datasource-plugin-influxdb-08, closes #3523

pkg/plugins/plugins.go

@@ -29,7 +29,9 @@ func Init() error {
 	Panels = make(map[string]PanelPlugin)
 
 	scan(path.Join(setting.StaticRootPath, "app/plugins"))
+	scan(path.Join(setting.PluginsPath))
 	checkExternalPluginPaths()
+
 	return nil
 }