Fix http response body not closed correctly, return immediately on error (#210)

* Fix controller timer handler not return when error occurred

* Fix controller not close http response correctly

This PR aims to fix controller not close response correctly. Also, I’ve check all over the project there is no more resource leak issues exist after this patch.

* Fix controller not return immediately when error occurred

* Sort import

poolmgr/functionServiceCache_test.go

@@ -3,9 +3,9 @@ package poolmgr
 import (
 	"log"
 	"testing"
+	"time"
 
 	"github.com/fission/fission"
-	"time"
 )
 
 func TestFunctionServiceCache(t *testing.T) {