smartools: fix nullptr access

This patch handles a nullptr returned by Manager::getCallFromCallID.

Change-Id: I0372099e4da315164cd0f617d6846d4dfac17f1e
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>

src/smartools.cpp

@@ -126,7 +126,11 @@ Smartools::setRemoteVideoCodec(const std::string& remoteVideoCodec, const std::s
 {
     std::lock_guard<std::mutex> lk(mutexInfo_);
     information_["remote video codec"]= remoteVideoCodec;
-    auto confID = Manager::instance().getCallFromCallID(callID)->getConfId();
+    auto call = Manager::instance().getCallFromCallID(callID);
+    if (!call) {
+        return;
+    }
+    auto confID = call->getConfId();
     if (confID != ""){
         information_["type"]= "conference";
         information_["callID"]= confID;