Merge pull request #435 from dragos-oancea/mod_voicemail_ivr-nullptr-arg

[mod_voicemail_ivr] scan-build: Null pointer passed as an argument to a 'nonnull' parameter - SWITCH_STANDARD_APP(voicemail_ivr_function)

src/mod/applications/mod_voicemail_ivr/mod_voicemail_ivr.c

@@ -68,7 +68,7 @@ SWITCH_STANDARD_APP(voicemail_ivr_function)
 	if (argv[2])
 		domain = argv[2];
 
-	if (!strcasecmp(argv[0], "check")) {
+	if (argv[0] && !strcasecmp(argv[0], "check")) {
 		if (argv[3])
 			id = argv[3];