fix typo (#1990)

conf/app.ini

@@ -119,7 +119,7 @@ SSH_PORT = 22
 SSH_LISTEN_PORT = %(SSH_PORT)s
 ; Root path of SSH directory, default is '~/.ssh', but you have to use '/home/git/.ssh'.
 SSH_ROOT_PATH =
-; Directory to create temporary files when test publick key using ssh-keygen,
+; Directory to create temporary files when test public key using ssh-keygen,
 ; default is system temporary directory.
 SSH_KEY_TEST_PATH =
 ; Path to ssh-keygen, default is 'ssh-keygen' and let shell find out which one to call.