upstream: fix: Check for necessary pointers in omemo_receive_message (25d2cb012)

src/xmpp/omemo.c

@@ -352,6 +352,10 @@ out:
 char*
 omemo_receive_message(xmpp_stanza_t* const stanza, gboolean* trusted)
 {
+    if (!stanza || !trusted || !error) {
+        return NULL;
+    }
+
     char* plaintext = NULL;
     const char* type = xmpp_stanza_get_type(stanza);
     const char* from = xmpp_stanza_get_from(stanza);