fix bug, linphone_core_accept_call will be crash when call is NULL, use by linphonec

[smallmuou]

Hi, Nearly i meet a issue, that when i use linphonec command to answer a call, it will crash. And I found it cause by linphone_core_accept_call(lc, NULL), see code bellow.

++++++++++console/commands.c++++++++
static int
lpc_cmd_answer(LinphoneCore *lc, char *args){
...
if ( -1 == linphone_core_accept_call(lc, NULL) )
{
linphonec_out("Fail to accept incoming call\n");
}
...
++++++++++++++++++++++++++++++++++

so I fix linphone_core_accept_call like this:

++++++++++coreapi/linphonecore.c++++++++

LinphoneStatus linphone_core_accept_call(LinphoneCore *lc, LinphoneCall *call) {
return linphone_core_accept_call_with_params(lc, call, NULL);
}
++++++++++++++++++++++++++++++++++

[abioteau]

👍