m) fix: quic server may assert failed when invalid SETTINGS frame in (#317)

ref: issue #316

src/liblsquic/lsquic_frame_reader.c

@@ -186,7 +186,7 @@ lsquic_frame_reader_new (enum frame_reader_flags flags,
 #endif
                     const struct lsquic_hset_if *hsi_if, void *hsi_ctx)
 {
-    struct lsquic_frame_reader *fr = malloc(sizeof(*fr));
+    struct lsquic_frame_reader *fr = calloc(1, sizeof(*fr));
     if (!fr)
         return NULL;
     fr->fr_mm             = mm;

src/liblsquic/lsquic_frame_writer.c

@@ -106,7 +106,7 @@ lsquic_frame_writer_new (struct lsquic_mm *mm, struct lsquic_stream *stream,
         return NULL;
     }
 
-    fw = malloc(sizeof(*fw));
+    fw = calloc(1, sizeof(*fw));
     if (!fw)
         return NULL;