ringmainwindow: prevent segmentation fault

Prevent a segmentation fault in function slotNewConversation

Gitlab: #1054
Change-Id: Iff82c5745b488a65663330f226a631773ba06c67
Reviewed-by: Philippe Gorley <philippe.gorley@savoirfairelinux.com>

src/ringmainwindow.cpp

@@ -2175,6 +2175,7 @@ CppImpl::slotNewConversation(const std::string& uid)
     auto* old_view = gtk_bin_get_child(GTK_BIN(widgets->frame_call));
     if (IS_RING_WELCOME_VIEW(old_view)) {
         accountInfo_->conversationModel->selectConversation(uid);
+        if (chatViewConversation_) {
             try {
                 auto contactUri =  chatViewConversation_->participants.front();
                 auto contactInfo = accountInfo_->contactModel->getContact(contactUri);
@@ -2182,6 +2183,7 @@ CppImpl::slotNewConversation(const std::string& uid)
             } catch(...) { }
         }
     }
+}
 
 void
 CppImpl::slotConversationRemoved(const std::string& uid)