Fix a segfault when handling errors or .asx or .ram files. Silly bug

on my part.

Originally committed as revision 536 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffserver.c

@@ -400,6 +400,7 @@ static int handle_http(HTTPContext *c, long cur_time)
             }
         } else {
             c->buffer_ptr += len;
+            if (c->stream)
                 c->stream->bytes_served += len;
             c->data_count += len;
             if (c->buffer_ptr >= c->buffer_end) {
@@ -1225,6 +1226,7 @@ static int http_send_data(HTTPContext *c)
         } else {
             c->buffer_ptr += len;
             c->data_count += len;
+            if (c->stream)
                 c->stream->bytes_served += len;
         }
     }