Don't blow up on an invalid AMA flag.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@283209 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/cel.c

@@ -349,6 +349,11 @@ const char *ast_cel_get_type_name(enum ast_cel_event_type type)
 
 const char *ast_cel_get_ama_flag_name(enum ast_cel_ama_flag flag)
 {
+	if (flag < 0 || flag >= ARRAY_LEN(cel_ama_flags)) {
+		ast_log(LOG_WARNING, "Invalid AMA flag: %d\n", flag);
+		return "Unknown";
+	}
+
 	return S_OR(cel_ama_flags[flag], "Unknown");
 }