InfluxDB: Close Flux query results (#26917)

* InfluxDB: Drop ctxhttp usage
* InfluxDB: Clean up code
* InfluxDB: Close query results

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/models/datasource_cache.go

@@ -45,7 +45,6 @@ var ptc = proxyTransportCache{
 
 func (ds *DataSource) GetHttpClient() (*http.Client, error) {
 	transport, err := ds.GetHttpTransport()
-
 	if err != nil {
 		return nil, err
 	}