- Fixed typo in usage

diff --git a/programs/x509/crl_app.c b/programs/x509/crl_app.c
index 96616de..b5c6c79 100644
--- a/programs/x509/crl_app.c
+++ b/programs/x509/crl_app.c
@@ -59,7 +59,7 @@
 #define USAGE \
     "\n usage: crl_app param=<>...\n"                   \
     "\n acceptable parameters:\n"                       \
-    "    filename=%%s         default: cert.crt\n"      \
+    "    filename=%%s         default: crl.pem\n"      \
     "    debug_level=%%d      default: 0 (disabled)\n"  \
     "\n"