avformat/utils: do not overwrite already existing program with defaults in av_new_program

av_new_program returns the existing program if that already exists, in that
case it makes no sense to overwrite existing attributes.

Signed-off-by: Marton Balint <cus@passwd.hu>

libavformat/utils.c

@@ -4590,14 +4590,12 @@ AVProgram *av_new_program(AVFormatContext *ac, int id)
         dynarray_add(&ac->programs, &ac->nb_programs, program);
         program->discard = AVDISCARD_NONE;
         program->pmt_version = -1;
-    }
         program->id = id;
         program->pts_wrap_reference = AV_NOPTS_VALUE;
         program->pts_wrap_behavior = AV_PTS_WRAP_IGNORE;
-
         program->start_time =
         program->end_time   = AV_NOPTS_VALUE;
-
+    }
     return program;
 }