close statement when missing query arguments

fixes #1280
diff --git a/sqlite3.go b/sqlite3.go
index ed2a9e2..ce985ec 100644
--- a/sqlite3.go
+++ b/sqlite3.go
@@ -929,6 +929,7 @@
 		s.(*SQLiteStmt).cls = true
 		na := s.NumInput()
 		if len(args)-start < na {
+			s.Close()
 			return nil, fmt.Errorf("not enough args to execute query: want %d got %d", na, len(args)-start)
 		}
 		// consume the number of arguments used in the current