bugs found

[SoonyangZhang]

sender_cc_create { cc->bitrate_controller = bitrate_controller_create(cc, sender_cc_on_change_bitrate);//line 41 cc->pacer = pace_create(handler, send_cb); } pacer is called before its created in sender_cc_on_change_bitrate, and segemnt fault.

{ cc->pacer = pace_create(handler, send_cb); cc->bitrate_controller = bitrate_controller_create(cc, sender_cc_on_change_bitrate); }