better error reporting and handling

weed-fs/src/pkg/operation/delete_content.go

@@ -2,11 +2,13 @@ package operation
 
 import (
 	"net/http"
+	"log"
 )
 
 func Delete(url string) error {
 	req, err := http.NewRequest("DELETE", url, nil)
 	if err != nil {
+		log.Println("failing to delete", url)
 		return err
 	}
 	_, err = http.DefaultClient.Do(req)