commandline: add static analyzer hint for -r parsing

src/suricata.c

@@ -1744,6 +1744,7 @@ static TmEcode ParseCommandLine(int argc, char** argv, SCInstance *suri)
 #endif /* IPFW */
             break;
         case 'r':
+            BUG_ON(optarg == NULL); /* for static analysis */
             if (suri->run_mode == RUNMODE_UNKNOWN) {
                 suri->run_mode = RUNMODE_PCAP_FILE;
             } else {