Fix typo in multinode-lab document

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Change-Id: I1b6100d6b8231f1f96a7768e26ab83f010f1e4dc
diff --git a/doc/source/guides/multinode-lab.rst b/doc/source/guides/multinode-lab.rst
index c0b3f58..dc3568a 100644
--- a/doc/source/guides/multinode-lab.rst
+++ b/doc/source/guides/multinode-lab.rst
@@ -395,7 +395,7 @@
 
 3. Verify that login via ssh works without a password::
 
-        ssh -i /root/.ssh/id_rsa.pub stack@DESTINATION
+        ssh -i /root/.ssh/id_rsa stack@DESTINATION
 
 In essence, this means that every compute node's root user's public RSA key
 must exist in every other compute node's stack user's authorized_keys file and