staging: lustre: ptlrpc: sec_plain: remove unneeded null test before free

Kfree can cope with a null argument, so drop null tests.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression ptr; @@

- if (ptr != NULL)
  kfree(ptr);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ptlrpc/sec_plain.c

@@ -384,8 +384,7 @@ struct ptlrpc_cli_ctx *plain_sec_install_ctx(struct plain_sec *plsec)
 	if (ctx) {
 		atomic_inc(&ctx->cc_refcount);
 
-		if (ctx_new)
-			kfree(ctx_new);
+		kfree(ctx_new);
 	} else if (ctx_new) {
 		ctx = ctx_new;