Fix handling of `--without-osx-keychain`

Refs: #3338
Change-Id: Ib9f7ff94d7436d618c5e9055f59b71f1e41893d5
diff --git a/docs/manpages/ndn-client.conf.rst b/docs/manpages/ndn-client.conf.rst
index f3d8500..010498d 100644
--- a/docs/manpages/ndn-client.conf.rst
+++ b/docs/manpages/ndn-client.conf.rst
@@ -75,7 +75,7 @@
 
   Possible values for ``[scheme]`` are:
 
-  * ``tpm-osx-keychain`` (default on macOS): secure storage of private keys in the macOS
+  * ``tpm-osxkeychain`` (default on macOS): secure storage of private keys in the macOS
     Keychain with OS-provided access restrictions.
 
     The ``[location]`` parameter is ignored.