Ensures cached stmt is finalized when not reusable.

cache.go

@@ -43,6 +43,7 @@ func (c *cache) find(sql string) *Stmt {
 			if s.SQL() == sql { // TODO s.SQL() may have been trimmed by SQLite
 				c.l.Remove(e)
 				if err := s.ClearBindings(); err != nil {
+					s.finalize()
 					return nil
 				}
 				return s