Crash when trying to answer calls but call has been disconnected

[ming]

When async media transport creation finished, it is possible that call might have been disconnected if application is answering with 200/OK and the media failed to start. This caused crash, below is the stack trace:

VoXIPTest.exe!pj_link_node(void * prev=0xdddddddd, void * next=0xdddddddd) Line 25 + 0x6 bytes C
VoXIPTest.exe!pj_list_erase(void * node=0x0124b684) Line 78 + 0x12 bytes C

VoXIPTest.exe!on_incoming_call_med_tp_complete(int call_id=1, const pjsua_med_tp_state_info * info=0x018bd3d4) Line 978 + 0x9 bytes C

VoXIPTest.exe!media_channel_init_cb(int call_id=1, const pjsua_med_tp_state_info * info=0x0418f3e8) Line 1693 + 0x1a bytes C
VoXIPTest.exe!call_media_init_cb(pjsua_call_media * call_med=0x018bcac8, int status=0, int security_level=0, int * sip_err_code=0x00000000) Line 1510 + 0x1a bytes C
VoXIPTest.exe!med_tp_timer_cb(void * user_data=0x018bcac8) Line 807 + 0x21 bytes C
VoXIPTest.exe!timer_cb(pj_timer_heap_t * th=0x01215f10, pj_timer_entry * entry=0x0122f92c) Line 2826 + 0x7 bytes C
VoXIPTest.exe!pj_timer_heap_poll(pj_timer_heap_t * ht=0x01215f10, pj_time_val * next_delay=0x0418f884) Line 518 + 0x10 bytes C
VoXIPTest.exe!pjsip_endpt_handle_events2(pjsip_endpoint * endpt=0x01215d1c, const pj_time_val * max_timeout=0x0418f8f0, unsigned int * p_count=0x0418f8f8) Line 714 + 0x10 bytes C
VoXIPTest.exe!pjsua_handle_events(unsigned int msec_timeout=10) Line 1691 + 0x14 bytes C
VoXIPTest.exe!worker_thread(void * arg=0x00000000) Line 634 + 0x7 bytes C
VoXIPTest.exe!thread_main(void * param=0x0122e520) Line 451 + 0xf bytes C

[ming]

(In [4118]) Fixed #1504: Crash when trying to answer calls but call has been disconnected