Revert "core: remove pointless re-initialisation of `stream_t` attributes"

This reverts commit b10f5a02.

as requested in follow-up discussion in !1104.

src/input/access.c

@@ -103,7 +103,9 @@ static stream_t *access_New(vlc_object_t *parent, input_thread_t *input,
 
     access->p_input_item = input ? input_GetItem(input) : NULL;
     access->out = out;
+    access->psz_name = NULL;
     access->psz_url = strdup(mrl);
+    access->psz_filepath = NULL;
     access->b_preparsing = preparsing;
     priv = vlc_stream_Private(access);
 

src/input/demux.c

@@ -156,6 +156,11 @@ demux_t *demux_NewAdvanced( vlc_object_t *p_obj, input_thread_t *p_input,
     p_demux->out            = out;
     p_demux->b_preparsing   = b_preparsing;
 
+    p_demux->pf_readdir = NULL;
+    p_demux->pf_demux   = NULL;
+    p_demux->pf_control = NULL;
+    p_demux->p_sys      = NULL;
+
     char *modbuf = NULL;
     bool strict = true;
 
@@ -449,9 +454,16 @@ static demux_t *demux_FilterNew( demux_t *p_next, const char *p_name )
     if (unlikely(p_demux == NULL))
         return NULL;
 
-    p_demux->s = p_next;
-
     priv = vlc_stream_Private(p_demux);
+    p_demux->s            = p_next;
+    p_demux->p_input_item = NULL;
+    p_demux->p_sys        = NULL;
+    p_demux->psz_name     = NULL;
+    p_demux->psz_url      = NULL;
+    p_demux->psz_location = NULL;
+    p_demux->psz_filepath = NULL;
+    p_demux->out          = NULL;
+
     priv->module = module_need(p_demux, "demux_filter", p_name,
                                p_name != NULL);
     if (priv->module == NULL)

src/input/stream_fifo.c

@@ -123,6 +123,7 @@ vlc_stream_fifo_t *vlc_stream_fifo_New(vlc_object_t *parent, stream_t **reader)
     sys = vlc_stream_Private(s);
     sys->writer = writer;
     s->pf_block = vlc_stream_fifo_Block;
+    s->pf_seek = NULL;
     s->pf_control = vlc_stream_fifo_Control;
     *reader = s;
     return writer;