Fixed mp4 if first entry in stsc was skipped (ticket #72).

If first entry in stsc atom was skipped, and seek was to chunk boundary,
than first_chunk in the generated stsc table wasn't set to 1.

src/http/modules/ngx_http_mp4_module.c

diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c
index 3c9f88c..7bfb3db 100644
--- a/src/http/modules/ngx_http_mp4_module.c
+++ b/src/http/modules/ngx_http_mp4_module.c
@@ -2382,6 +2382,8 @@
     data->pos = (u_char *) entry;
     atom_size = sizeof(ngx_mp4_stsc_atom_t) + (data->last - data->pos);
 
+    ngx_mp4_set_32value(entry->chunk, 1);
+
     if (trak->chunk_samples) {
 
         first = &trak->stsc_chunk_entry;