swtpm_localca: Add missing NULL option to end of array

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
diff --git a/src/swtpm_localca/swtpm_localca.c b/src/swtpm_localca/swtpm_localca.c
index a509fb9..2854c31 100644
--- a/src/swtpm_localca/swtpm_localca.c
+++ b/src/swtpm_localca/swtpm_localca.c
@@ -585,6 +585,7 @@
         {"allow-signing", no_argument, NULL, 'i'},
         {"decryption", no_argument, NULL, 'y'},
         {"help", no_argument, NULL, 'h'},
+        {NULL, 0, NULL, 0},
     };
     g_autofree gchar *default_options_file = NULL;
     g_autofree gchar *default_config_file = NULL;